13 Immunology (161) Flashcards
Case
A 43-year-old woman presents with a history of itchy eyes, dry mouth, and changes in her facial appearance for the past few months. During the physical exam, the patient shows dry eyes, white patches on the tongue, and enlargement of the parotid glands. There is no clinical evidence of active arthritis.
What antibody is most likely be positive in this patient?
1 Cytoplasmic antineutrophil cytoplasmic autoantibodies (C-ANCA)
2 Anti-DNA topoisomerase I antibodies (Scl-70)
3 Antinuclear antibodies AntiSm
4 Antinuclear antibodies ds-DNA
5 Anti-ribonucleoprotein antibodies SS-A (Ro)
Anti-ribonucleoprotein antibodies SS-A (Ro)
Sjögren syndrome is an autoimmune disease, most common in women, manifested usually by dry eyes and dry mouth as result of destruction of the lacrimal and parotid glands, which are enlarged (Mikulicz syndrome). These patients can also have mild arthritis, but sometimes Sjögren syndrome may also be associated with other autoimmune diseases, such as SLE, where the compromise of the joints can be more severe. Anti-ribonucleoprotein antibodies SS-A (Ro) and SS-B (La) are positive. Recent studies show that there are specific kinds of anticentromere antibodies that can be also positive.
Cytoplasmatic antineutrophil cytoplasmatic autoantibodies (C-ANCA) are positive in granulomatosis with polyangiitis.
Anti-DNA topoisomerase I antibodies (Scl-70) are positive in patients with diffuse scleroderma.
Antinuclear antibodies AntiSm and antinuclear antibodies ds-DNA are positive in systemic lupus erythematosus (SLE).
A 9-year-old boy presents with a rash on his buttocks. The patient states that the rash has been present for the past few days and is accompanied with joint pain in his knees and wrists. Blood work is drawn and is notable for a serum creatinine clearance of 1.3mg/dL. Vital signs are normal. Physical exam demonstrates palpable purpura on the buttocks. There is mild tenderness in the knee and wrist joints. The patient was diagnosed with Henoch-Schonlein purpura. Which of the following is the most likely mechanism of this disease?
1 Type I hypersensitivity
2 Type II hypersensitivity
3 Type III hypersensitivity
4 Type IV hypersensitivity
5 Type V hypersensitivity
Type III hypersensitivity
Henoch-Schonlein purpura occurs due to type III hypersensitivity reaction or immune-complex mediated reaction. Henoch-Schonlein purpura is a disease characterized by palpaple purpura, joint pain, gastrointestinal symptoms, and glomerulonephritis. The disease is usually seen in children, and is more common in boys than in girls. The mechanism of Henoch-Schonlein is a type III hypersensitivity also known as immune complex hypersensitivity. Other examples include serum sickness, SLE, arthus reactions, and rheumatoid arthritis.
Type I hypersensitivity is also known as immediate or anaphylactic hypersensitivity.
Type II hypersensitivity is also known as cytotoxic hypersensitivity. The antigens are normally endogenous, although chemicals (i.e. drugs) can also lead to type II hypersensitivity. A classic example is myasthenia gravis.
Type IV is also known as delayed type hypersensitivity and is seen in tuberculosis, and poison ivy (contact dermatitis).
A reaction in which a directly stimulatory autoantibody acts through a target receptor is called Type V hypersensitivity reaction. An example is Graves’ disease in which the antibody against the TSH receptor stimulates the thyroid gland to cause hyperthyroidism.
You perform a kidney transplant on a 62 year-old male. Unfortunately, the lab mis-typed the organ and your patient begins to reject the graft within a week of receiving it. As your patient’s macrophages and cytotoxic T cells begin to reject the grafted organ, what cells specifically are they rejecting?
Answer Choices
1 Cells of the loop of Henle
2 Capillary endothelial cells
3 Granular juxtaglomerular cells
4 Glomerular capsular cells
5 Cells of the collecting tubules
Capillary endothelial cells
The first cells that the host’s immune system encounter are those of the capillaries in which they travel. All of the immune response is directed against these cells. Microthrombi form in the capillary beds of the transplanted organ and it dies from hypoxia.
A proud mother brings her healthy, six week old daughter in to your office for her first “shots.” As your nurse administers the vaccine, you reflect upon what you know about vaccines and humoral immunity. You realize that this infant is naive to the antigen that is being introduced to her system, so her initial antibody response will be weak. You take comfort in that subsequent introductions of the antigen will produce a more protective immune response. What class of antibodies will be produced by your young patient against the vaccine?
1 IgG1
2 IgG2
3 IgG3
4 IgM
5 IgE
IgM
Under normal circumstances, IgM is produced during the initial response to an antigen. Subsequent exposure to the same antigen results in class-switching by the B cells to produce IgG1.
What characteristics of IgM make it a good antibody for initial exposure to an antigen?
1 It does not fix complement very well, so it would be less likely for host cells to be damaged by complement
2 Its pentameric structure make it ideal for being secreted and binding to mucosal surfaces to protect the body from invading
organisms
3 Its low affinity and high avidity make it less specific but highly effective at binding to invading antigens
4 In its monomeric form, it binds readily to the surface of mast cells, which, in turn, can release inflammatory mediators that will help eliminate the antigen
Its low affinity and high avidity make it less specific but highly effective at binding to invading antigens
IgM is an excellent fixer of complement. Its pentameric form precludes IgM from leaving systemic circulation. Initial production of IgM has lower affinity but higher avidity due to multiple binding sites. This provides less opportunities for the antigen to escape. Monomeric IgM binds to B cells, not mast cells.
Which of the following interleukins that are produced by macrophages stimulate T helper 1 cell activity?
1 IL-1
2 IL-6
3 IL-12
4 TNF-α
5 IL-4
IL-12
IL-1 stimulates T helper 2 cell activity. IL-6 stimulate antibody production by B cells. IL-12 stimulates Th1 cells to produce IL-2 and IFN-α. TNF-α is not an interleukin. IL-4 is produced by Th2 cells.
In which of the following scenarios will tolerance to a foreign antigen be induced in T cells?
1 Binding of antigen by the TCR, but lack of secondary signal mediated through CD 28
2 During development, binding of MHC expressed on thymocytes by TCR on developing T cells
3 Specific antigens such as pneumococcal polysaccharide block the TCR, preventing further activation
4 Repeated exposure to high concentrations of antigen will result in clonal exhaustion
5 Addition of an antigen with an adjuvant will induce tolerance
Binding of antigen by the TCR, but lack of secondary signal mediated through CD 28
Binding of TCR and CD 28 is required for activation of a T cell. If TCR only is bound, the T cell will not respond to the antigen. While recognition of MHC on thymocytes is essential for T cells to become tolerant, this tolerance is to self-antigens. Certain antigens such as pneumococcal antigen or repeated exposure to high concentrations of antigen will induce tolerance in B cells, and have not been demonstrated to induce tolerance in T cells. Addition of an adjuvant to an antigen is a way to break tolerance.
Which of the following is an example of Type II hypersensitivity?
1 Acute serum sickness
2 Chronic serum sickness
3 Hemolytic disease of the newborn
4 Hypersensitivity pneumonitis
5 Metal allergies
Hemolytic disease of the newborn
Type II hypersensitivity is usually mediated through antibodies and complement and is directed against erythrocytes. Acute & chronic serum sickness as well as hypersensitivity pneumonitis are initiated by immune complex deposition within the walls of a capillary bed, and are examples of type III hypersensitivity. Metal allergies are classified as type IV hypersensitivity.
A delayed hypersensitivity reaction is characterized by
1 An infiltrate composed of eosinophils
2 An infiltrate composed of lymphocytes and macrophages
3 An infiltrate composed of neutrophils
4 Edema without cellular infiltrate
An infiltrate composed of lymphocytes and macrophages
Delayed hypersensitivity is a function of helper (CD4) T lymphocytes. The response starts hours after contact with antigen. It consists of mainly mononuclear cell infiltration (macrophages and helper [CD4] T cells) and tissue induration, an example of which is the tuberculin test.
Acute poststreptococcal glomerulonephritis is characterized by:
1 Low complement levels and lumpy deposits of immunoglobulin and C3 seen along the glomerular basement membranes
2 High levels of complement
3 Intravascular clumping of platelets
4 Tissue induration
Low complement levels and lumpy deposits of immunoglobulin and C3 seen along the glomerular basement membranes
Acute poststreptococcal glomerulonephritis is a well-accepted immune-complex disease. Its onset follows several weeks after a group A beta-hemolytic streptococcal infection esp with nephritogenic serotypes of Streptococcus pyogenes . The complement levels are low and lumpy deposits of immunoglobulin and C3 are seen along glomerular basement membranes by immunofluorescence suggesting the presence of antigen-antibody complexes. It is postulated that streptococcal antigen-antibody complexes, after being deposited on glomeruli, fix complement and attract neutrophils, which start the inflammatory process.
The principal difference between cytotoxic (type II) and immune complex (type III) hypersensitivity is
1 The participation of T cells
2 The participation of complement
3 The distribution of antigen-antibody complexes
4 The class (isotype) of antibody
The distribution of antigen-antibody complexes
Cytotoxic hypersensitivity occurs when antibody directed at antigens of the cell membrane activates the complement. This generates a membrane attack complex, which damages the cell membrane. Immune-complex hypersensitivity occurs when antigen-antibody complexes induce an inflammatory response in tissues. The immune complexes occasionally persist and are deposited in tissues, resulting in several disorders.
AIDS is caused by a human retrovirus that kills
1 CD8-positive T lymphocytes
2 CD4-positive T lymphocytes
3 Lymphocyte stem cells
4 B lymphocytes
CD4-positive T lymphocytes
Patients with AIDS have greatly reduced helper T cell numbers caused by infection with the retrovirus that specifically infects cells with the CD4 receptor. The HIV virus has type-specific envelope glycoproteins called gp120 and gp41. gp120 protrudes from the surface and interacts with the CD4 receptor on the cell surface. gp41 is embedded in the envelope and mediates the fusion of the viral envelope with the cell membrane at the time of infection.
An 11-year-old boy goes on his first camping trip to a National forest with his scout troop. Upon arrival, he eagerly hikes through the forest to the campout area to pitch his tent. The next day he complains of intense itching and has blistering on his hands, arms and legs. What is the most likely diagnosis?
1 Serum sickness
2 Hay fever
3 Arthus reaction
4 Contact dermatitis
5 Farmer’s lung disease
Contact dermatitis
The boy likely has allergic contact dermatitis (contact hypersensitivity) where he may have encountered poison oak or poison ivy in the forest or in the camp area. Contact dermatitis is a cell-mediated, type IV hypersensitivity reaction. Poison ivy or oak produces urushiols (small molecular weight oils on the leaves that act as immunogens) that penetrate the skin and act as haptens after binding to large carrier proteins to become complete antigens. No one is born with sensitivity to poison ivy but if exposed enough most people become sensitized and remain allergic. The sensitized person develops erythema, itching fluid-filled vesicles, and sometimes necrosis generally seen within 12-48 hours after contact.
Hay fever, or allergic rhinitis, is usually caused by pollen spores, and can occur within minutes of exposure to an allergen.
Serum sickness is an example of type III hypersensitivity and is an immune complex disease in which antibodies to foreign proteins are produced. Serum sickness is now caused by drugs (not serum) and is manifested by fever, itching, arthralgias, proteinuria, and lymphadenopathy which occur 5-10 days after antigen exposure.
Arthus reaction is a local subacute antibody-mediated type III hypersensitivity reaction. Intradermal injection of the antigen induces antibodies which form antigen-antibody complexes in the skin causing edema, necrosis, and activation of complement. An example is hypersensitivity pneumonitis.
Farmer’s lung disease results from inhalation of spores from Actinomycetes species such as in moldy hay. Early lesions are thought to be an immune complex type III hypersensitivity followed by granulomatous interstitial inflammation of the lungs characteristic of type IV cell-mediated responses. Farmer’s lung disease is the most frequently reported type of hypersensitivity pneumonitis.
Which of the following statements about processing of exogenous and endogenous antigen is correct?
1 Exogenous antigen is processed by B cells, macrophages, and dendritic cells and presented to T cells on MHC class I molecules
2 Endogenous antigen is processed by B cells, macrophages, and dendritic cells and presented to T cells on MHC class I molecules
3 Endogenous antigen is processed by body cells and presented to B cells on MHC class II molecules
4 Endogenous antigen is processed by body cells and presented to T cells on MHC class I molecules
5 Exogenous antigen is processed by body cells and presented to T cells on MHC class II molecules
Endogenous antigen is processed by body cells and presented to T cells on MHC class I molecules
Exogenous antigen is antigen taken up by antigen-presenting cells (macrophages, B cells, and dendritic cells) and presented on MHC class II molecules to T cells. Endogenous antigen is processed by cells of the body and presented to CD 8 T cells on MHC class I molecules. Expression of MHC class II is limited to cells of the immune system.
Which of the following best describes thymic independent antigens?
1 Somatic antigens that are presented outside the thymus
2 Antigens that activate the immune response without relying upon T cells
3 Antigens that are presented to T cells in sites other than the thymus
4 Antigens that induce the immune response in cells that mature within the thymus
5 Antigens that are protein in nature
Antigens that activate the immune response without relying upon T cells
Thymic independent antigens are antigens that stimulate an immune response without the presence of T helper cells. These are often bacterial carbohydrates such as pneumococcal polysaccharides.
CD 4+ lymphocytes play an active role in all but which of the following functions?
1 Activate cytotoxic T cells
2 Activate macrophages
3 Stimulate B cells to produce antibody
4 Present antigen
5 Secrete lymphokines
Present antigen
Antigen presentation is carried out by B cells, macrophages, and dendritic cells. CD 4 + T cells are “helper” cells that serve to activate both humoral and cell-mediated immunity.
CD 8+ lymphocytes play an active role in all but which of the following functions?
1 Lyse virally infected cells
2 Lyse tumor cells
3 Stimulate B cells to produce antibody
4 Suppress inappropriate immune
responses
5 Secrete lymphokines
Stimulate B cells to produce antibody
CD 8 + lymphocytes use MHC class I molecules to check for the presence of endogenous antigens. These antigens are produced in virally infected cells as well as is some tumor cells. Additionally, CD 8 + cells play a major role in avoidance of autoimmunity by either direct suppression or lysis of immune cells that respond to autoantigens. These cells secrete lymphokines as part of the immune response
B cells play an active role in all but which of the following functions?
1 Production of antibody
2 Secretion of lymphokines
3 Presentation of antigen
4 Induction of Type I hypersensitivity
5 Induction of Type IV hypersensitivity
Induction of Type IV hypersensitivity
B cells are primarily producers of antibodies. They do present antigen and secret low levels of lymphokines when doing so. IgE produced by B cells is instrumental in Type I hypersensitivity, or anaphylaxis. Type IV hypersensitivity is not mediated by antibodies
The immunoglobulin IgA is found primarily in what locations in the body?
1 On mucosal surfaces
2 In the serum
3 On the surface of mast cells
4 In the aqueous humor
5 In CNS
On mucosal surfaces
IgA is found primarily on mucosal surfaces. Although there is small amounts in circulation, it is found bound to bilirubin and other substances.
Which lymphokine initiates switching from IgM/IgD production to IgE production in B cells?
1 IL-2
2 IL-4
3 IL-5
4 IFN-γ
5 TNF-γ
IL-4
Interleukin 4 initiates switching from production of IgM/IgD to IgE in B cells. This is blocked by IFN-γ. Immunotherapy, or “allergy shots,” attempts to stimulate Th1 cells to produce IFN-γ.
Identify the immunological disease that results in high levels of IgE, but also the inability of neutrophils to respond to chemotactic stimuli.
1 Job’s syndrome
2 Chediak-Higashi syndrome
3 Wiskott-Aldrich syndrome
4 Fanguys syndrome
5 X-linked granulomatous disease
Job’s syndrome
Defects in antigen processing cells and innate immune response often lead to a wide variety of syndromes. Job’s syndrome is characterized by neutrophils that are unable to respond to chemotaxins.
Identify the immunological disease that results from a deficiency in C1 esterase inhibitor resulting in the indirect generation of vasoactive kinins
1 X-linked agammaglobulinemia
2 Hereditary angioedema
3 Common variable hypogammaglobulinemia
4 Adenosine deaminase and nucleotide phosphorylase deficiency
5 DiGeorge syndrome
Hereditary angioedema
When C1 esterase inhibitor is not produced, excessive production of vasoactive kinins results. This causes angioedema.
Identify the immunological disease that results in the inability to produce a specific immunoglobulin, attributable to recurrent bacterial infections during adolescence
1 X-linked agammaglobulinemia
2 Hereditary angioedema
3 Common variable hypogammaglobulinemia
4 Adenosine deaminase and nucleotide phosphorylase deficiency
5 DiGeorge syndrome
Common variable hypogammaglobulinemia
It is thought that recurrent bacterial infections during young adulthood, in concert with exhaustion of plasma cells leads to the loss of the ability to produce effective, long-term antibody protection.
Which of the following best describes DiGeorge syndrome?
1 Mild facial hypoplasia with below average levels of circulating immunoglobulins
2 Mild facial hypoplasia with inability of macrophages to process antigen
3 Mild facial hypoplasia with deficiencies in T cell number and function
4 Mild facial hypoplasia with high levels of serumal IgE
5 Mild facial hypoplasia with low affinity, low avidity binding capacity of IgG
Mild facial hypoplasia with deficiencies in T cell number and function
DiGeorge syndrome is a congenital hypoplasia of the IIIrd and IV th pharyngeal arches resulting in facial, thymic and parathyroid hypoplasia. T cell numbers and functions are drastically decreased. Transplants of thymic tissues are currently being evaluated as a treatment modality for DiGeorge syndrome.
The following cytokine is involved in generating a major part of the Down syndrome phenotype.
1 Interferon
2 Interleukin
3 Plasminogen activator
4 Tumor necrosis factor
Interferon
The region responsible for most of the Down syndrome phenotype includes the genes for two subunits of the interferon α receptor. This leads to overactivity of interferon α action. The table below compares the Down Syndrome Anomalies with the interferon α side effects.
Down Syndrome
Anomalies Interferon Side Effects
Intellectual Disability Neurotoxicity, Memory Loss
Frontal lobe dysphasia Frontal lobe encephalopathy
Heart Anomalies Cardiotoxicity, Arrhythmia
Leukopenia Leukopenia
Autoimmune disease Autoimmune disease
Hypothyroidism Hypothyroidism
Hearing Loss Deafness
Short Stature Growth Inhibition
This cytokine is involved in the pathogenesis of Euthyroid Sick syndrome (low T3 syndrome) through its ability to inhibit type I 5’-deiodinase
1 Interferon
2 Interleukin
3 Plasminogen activator
4 Tumor necrosis factor
Tumor necrosis factor
In major acute or chronic illness, inflammatory cells will secrete cytokines such as tumor necrosis factors (TNF). TNF is capable of inhibiting type I 5’-deiodinase, allowing for acceleration of inner ring deiodination of thyroxine (T4). This leads to low circulating levels of triiodothyronine (T3), and increased levels of reverse triiodothyronine (rT3).
The smallest unit of a complex antigen capable of binding to an antibody is a(n)
1 Immunogen
2 Epitope
3 Hapten
4 Adjuvant
5 Carrier molecule
Epitope
Epitopes are an integral part of an antigen molecule that binds with an antibody. Epitopes are also known as antigenic determinants, as they determine the specificity of the antigen molecule. Epitopes can exist in sequential form or conformational form.
Haptens are small molecules that bind to carrier molecules and become immunogenic.
Adjuvants are substances that enhance the immunogenicity of molecules without changing their chemical structure.
A carrier molecule is an immunogenic molecule, such as a foreign protein, to which a hapten is coupled, thus, enabling the hapten to induce an immune response.
Antigens that are found in genetically different members of the same species are called
1 Heterologous antigens
2 Autologous antigens
3 Syngeneic antigens
4 Allogeneic antigens
5 Xenogeneic antigens
Allogeneic antigens
Allogeneic antigens are found in genetically different members of one’s own species
Heterologous antigen are also called xenogeneic antigens and are present in different species
Autologous antigens are self antigen found in an individual
Syngeneic antigens are found in genetically identical individuals
Which of the following antibodies is found in the highest concentration in serum?
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgG
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
The antibody that can cross the placenta and can fix the complement is
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgG
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
The antibody that is a pentamer and is first to appear in an immune response is:
Answer Choices
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgM
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
The antibody with 10 antigen binding sites is
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgM
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
The antibody predominant in milk, saliva, and tears is
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgA
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
What is the antibody responsible for mucous membrane protection from bacterial and virus attack?
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgA
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
The high level of this antibody is found in people with immediate allergic hypersensitivity and is called
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgE
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
The antibody which mediates the release of histamine and heparin is
1 IgA
2 IgD
3 IgE
4 IgG
5 IgM
IgE
IgG is the predominating antibody in serum and contributes to 75% to 85% to total immunoglobulin concentration. IgG is responsible for protection of the fetus, as it is the only immunoglobulin that can cross the placenta. It is divalent molecule and is made up of 2 H chains and 2 lights chain. IgG is divided into four subclasses: IgG1, IgG2, IgG3, and IgG4, according to antigenic differences in the H chain and the number and location of disulfide bonds. IgG is also involved in Rh disease of the newborn. It is produced in high concentration during secondary immune response.
IgM can fix the complement but cannot cross the placenta. It is the largest immunoglobulin and is a pentamer made up of 5 H2L2 units and 1 molecule of J chain. It has 10 antigen binding sites and has the highest avidity. It is first antibody to appear in an immune response.
IgA is produced by B cells and is found in high concentrations in tears, saliva, milk, and other secretions. It is a monomer made up of 1 4-chain unit.
IgE is a monomer that is present in very low concentration in serum. Increased level of IgE is found in antibody mediated allergic hypersensitivity and in parasitic infections. The mast cells and the basophils are involved in allergic response and have Fc receptors specific for IgE antibodies. The IgE antibodies serve as antigen receptor and can cause mast cells and basophils to release inflammatory mediators like histamine and heparin.
Ig D is a monomer comprised of 4-chain unit and is found on the surface of B lymphocytes. It is found in very low concentration in serum.
IgA, IgE, and IgD do not fix the complement and cannot cross the placenta.
What is IgM
1 A pentamer
2 Has five antigen binding site
3 Can cross the placenta
4 Is predominant in secretion
5 Does not participate in agglutination reaction
A pentamer
IgM is a pentamer made up of five H2L2 units and one molecule of J chain. It has ten antigen binding sites and is excellent agglutinating antibody. It is the first antibody to appear in an immune response IgM can fix the complement and can kill the bacterial cell by cytolysis. IgM is the largest immunoglobulin and can not cross the placenta.
The predominating antibody in the secretions is IgA.
Which of the following forms an antigen binding site in an immunoglobulin molecule?
1 Amino terminal of each light chain of constant region
2 Carboxy terminal of constant heavy chain
3 Amino terminal of variable light and heavy chain
4 Carboxy terminal of variable heavy chain
5 Amino terminal of constant heavy and constant light chain
Amino terminal of variable light and heavy chain
Variable region of light chain and heavy chains consists of N-terminal that shows variation in amino acid sequences. Amino terminal of this region forms an antigen binding site.
Constant region consists of carboxy terminal and does not demonstrate variation in amino acid sequences. This region is responsible for biological functions.
Ataxia telangiectasia is
1 X-linked recessive syndrome
2 A combined defect of both cellular and humoral immunity
3 Characterized by elevated IgA levels
4 Associated with defective neutrophil function
5 An acquired C3 deficiency
A combined defect of both cellular and humoral immunity
Ataxia telangiectasia is an autosomal recessive syndrome characterized by a combined defect of both cellular and humoral immunities. Cerebellar ataxia (staggering) and telangiectasia (enlargement of blood vessels) especially affecting earlobe and conjunctiva are seen in this syndrome. Recurrent infections occur as antibody response to antigen is inhibited. Patient suffering from ataxia telangiectasia often demonstrates reduced levels of IgA, IgE, and IgG2, and decrease in circulating T lymphocytes.
Which of the following cells can retain the memory of prior contact with an antigen?
1 B lymphocytes
2 Macrophages
3 Basophils
4 Thrombocytes
5 Neutrophils
B lymphocytes
Lymphocytes are the only immunologically specific cellular component of the immune system. Lymphocytes are responsible for primary recognition of an antigen. Antigen binding to B lymphocyte results in the enlargement, proliferation, and differentiation of lymphocytes. Some of the proliferating cells do not differentiate into plasma cells but instead revert to a resting state to become memory B lymphocytes. These memory cells survive for years within lymphoid follicles and produce more memory and effector cells upon activation by antigens.
Macrophages are involved in phagocytosis, antigen presentation, and induction of immune response
Basophils consists of heparin and histamine in their granules and participate in acute and systemic hypersensitivity reactions.
Thrombocytes are also known as platelet and participate in the clotting mechanism of the body.
Neutrophils are the principle leukocytes associated with phagocytosis and localized inflammatory response.
Individuals of blood group type O
1 Have O antigen on their red blood cells
2 Have A antigen and B antigen on their red blood cells
3 Have neither A nor B antigen on their red blood cells
4 Lack anti-A and anti-B antibodies
5 Lack anti-A antibody
Have neither A nor B antigen on their red blood cells
Blood group antigens are found on red blood cells in the blood. Antibodies to specific blood group are found in all individual that lack that antigen. Type O individuals lack A and B antigens therefore they have both anti-A and anti-B antibodies. Hemagglutination reaction is used to type blood groups and match compatibility between donors and recipients for blood transfusion.
Type AB individuals have A antigen and B antigen on their red blood cells and therefore lack anti-A and anti-B antibodies.
Type A individuals have A antigens on their red blood cells and therefore lack anti-A antibody and contain anti-B antibody.
Type B individuals have B antigens on their red blood cells and therefore lack anti-B antibody and contain anti-A antibody.
Which of the following immunologic reaction involves combination of soluble antigen with soluble antibody to produce insoluble complexes?
1 Complement fixation
2 Agglutination
3 Immunofluorescence
4 Precipitation
5 Flocculation
Precipitation
Precipitation involves the interaction of soluble antigen with a soluble antibody in correct proportion, leading to a visible precipitate. Precipitation reaction is effected by the amount of antigen and antibody present. The largest amount of precipitate is found in zone of equivalence.
Complement fixation is triggering of the classical complement pathway resulting from the combination of antigen with specific antibody.
Agglutination reaction results when particulate antigens aggregate to form larger complexes in presence of specific antibody.
Flocculation is an antigen-antibody reaction where antigen is an insoluble particulate.
Immunofluorescence involves the use of fluorescence microscope and is used for antigen detection in cells or tissues through the use of specific antibody labeled with fluorescent compound.
Which of the following tests is used for confirmation of HIV infection?
1 Western blot assay
2 Enzyme linked immunosorbent assay
3 PPD test
4 RPR test
5 Rose-Waaler test
Western blot assay
Enzyme linked immunosorbent assay (ELISA) is used as a screening test for HIV infection. When results for ELISA for antibody to HIV is positive, western blot is used to determine if the results are true positive or false positive.
Western blot assay is used as a confirmatory test to detect antibodies to HIV-1, human immunodeficiency virus. Western blot is an adaptation of immunofixation electrophoresis and is used to detect the antibodies to organisms of complex antigenic composition. HIV antigens are electrophoresed in a gel, resulting in the separation of individual viral proteins. These viral proteins are then transferred to nitrocellulose paper by means of blotting, and the patient’s serum is applied over it. If antibodies are present, they bind to viral proteins and can be detected by addition of antibody to human IgG labeled with either radioactive material or an enzyme, which produces a visible color change.
Rose-Waller test is used for detection of rheumatoid factor.
PPD test or purified protein derivative test is a skin test available to detect sensitization with Mycobacterium tuberculosis
RPR test or rapid plasma reagin test is a screening test used for diagnosis of syphilis.
Which of the following methods is most sensitive for measurements of antigen and antibody?
1 Precipitation
2 Indirect enzyme linked immunosorbent assay
3 Bacterial agglutination
4 Immunoelectrophoresis
5 Passive hemagglutination
Indirect enzyme linked immunosorbent assay
Indirect or noncompetitive enzyme linked immunosorbent assay (ELISA) has higher sensitivity (0.0005μg/mL) and is used for qualitative and quantitative determination of unknown antibodies in patient’s specimen. In this method, an antigen is bound to solid phase, and unlabeled patient antibody is added and given time to react. Following the wash step, an enzyme labeled antiglobulin is added. The second labeled antibody reacts with the Fc portion of the patient’s antibody that is bound to solid phase. In absence of a specific antibody, there is no binding of second labeled antibody. In the wash step, all unbound labeled antibody is removed. In the next step, substrate is added and color development is measured. Color development is directly proportional to the amount of antibody in patient’s serum.
Indirect ELISA is more sensitive, and sensitivity of nanogram is achieved because all patient ligand has chance to participate in the reaction.
Sensitivity for precipitation and immunoelectrophoresis method is ~20μg/mL for antibody detection
Sensitivity for bacterial agglutination and passive hemagglutination methods is ~0.01μg/mL for antibody detection.
Three basic reaction patterns result from the relationship of antigen and antibody in Ouchterlony double diffusion technique. Which of the following observations is made with partial identity?
1 Lines of precipitation run parallel to each other
2 Lines of precipitation merge with spur formation
3 Lines of precipitation coming together forming a smooth curve
4 Lines of precipitation cross each other
5 Lines of precipitation form two concentric circles
Lines of precipitation merge with spur formation
In the Ouchterlony double diffusion technique, both antigen and antibody diffuse independently through the medium in vertical and horizontal dimensions. In this method, wells are cut into an agar plate, and antigens and antisera are placed in the wells. The diffusion results in formation of a visible precipitation band at the zone of equivalence. When an antibody is placed in the center well and antigens are placed in the surrounding wells, three basic reaction are possible depending on the relationship between the antigens and antibody.
Reaction of partial identity is indicated when precipitation line fuses with spur formation. This reaction occurs when antigens being tested are nonidentical but do share common determinants.
Reaction of identity is revealed when the precipitation lines meet at a point and form a smooth curve or arc. This type of precipitin band indicates that antibody is precipitating identical antigen specificities in each preparation. Lines of identity does not necessarily mean that the antigens are identical. It only represents serological identity or presence of common determinants.
Reaction of nonidentity is demonstrated by formation of precipitation lines crossing one another. Precipitin bands intersect each other, as they do not have common antigenic determinants.
Ouchterlony double diffusion technique is used for semi quantitative determinations of antigens or antibodies and to determine the purity and relatedness of the reactants.
Three basic reaction patterns result from the relationship of antigen and antibody in Ouchterlony double diffusion technique. Which of the following observations is made with identity?
1 Lines of precipitation run parallel to each other
2 Lines of precipitation merge with spur formation
3 Lines of precipitation coming together forming a smooth curve
4 Lines of precipitation cross each other
5 Lines of precipitation form two concentric circles
Lines of precipitation coming together forming a smooth curve
In the Ouchterlony double diffusion technique, both antigen and antibody diffuse independently through the medium in vertical and horizontal dimensions. In this method, wells are cut into an agar plate, and antigens and antisera are placed in the wells. The diffusion results in formation of a visible precipitation band at the zone of equivalence. When an antibody is placed in the center well and antigens are placed in the surrounding wells, three basic reaction are possible depending on the relationship between the antigens and antibody.
Reaction of partial identity is indicated when precipitation line fuses with spur formation. This reaction occurs when antigens being tested are nonidentical but do share common determinants.
Reaction of identity is revealed when the precipitation lines meet at a point and form a smooth curve or arc. This type of precipitin band indicates that antibody is precipitating identical antigen specificities in each preparation. Lines of identity does not necessarily mean that the antigens are identical. It only represents serological identity or presence of common determinants.
Reaction of nonidentity is demonstrated by formation of precipitation lines crossing one another. Precipitin bands intersect each other, as they do not have common antigenic determinants.
Ouchterlony double diffusion technique is used for semi quantitative determinations of antigens or antibodies and to determine the purity and relatedness of the reactants.
Three basic reaction patterns result from the relationship of antigen and antibody in Ouchterlony double diffusion technique. Which of the following observations is made with nonidentity?
1 Lines of precipitation run parallel to each other
2 Lines of precipitation merge with spur formation
3 Lines of precipitation coming together forming a smooth curve
4 Lines of precipitation cross each other
5 Lines of precipitation form two concentric circles
Lines of precipitation cross each other
In the Ouchterlony double diffusion technique, both antigen and antibody diffuse independently through the medium in vertical and horizontal dimensions. In this method, wells are cut into an agar plate, and antigens and antisera are placed in the wells. The diffusion results in formation of a visible precipitation band at the zone of equivalence. When an antibody is placed in the center well and antigens are placed in the surrounding wells, three basic reaction are possible depending on the relationship between the antigens and antibody.
Reaction of partial identity is indicated when precipitation line fuses with spur formation. This reaction occurs when antigens being tested are nonidentical but do share common determinants.
Reaction of identity is revealed when the precipitation lines meet at a point and form a smooth curve or arc. This type of precipitin band indicates that antibody is precipitating identical antigen specificities in each preparation. Lines of identity does not necessarily mean that the antigens are identical. It only represents serological identity or presence of common determinants.
Reaction of nonidentity is demonstrated by formation of precipitation lines crossing one another. Precipitin bands intersect each other, as they do not have common antigenic determinants.
Ouchterlony double diffusion technique is used for semi quantitative determinations of antigens or antibodies and to determine the purity and relatedness of the reactants.
Select the most correct statement concerning antigen antibody reaction.
1 Optimum precipitation occurs in area of antigen excess
2 Rocket immunoelectrophoresis is slower than radial immunodiffusion and can not be used for immunoglobulin quantitation
3 Immunoelectrophoresis procedure is used for identification of Bence Jones proteins in myeloma
4 Western blot test is an adaptation of passive agglutination technique
5 Nephelometry can not be used for quantitative measurements of immunoglobulins
Immunoelectrophoresis procedure is used for identification of Bence Jones proteins in myeloma
Immunoelectrophoresis procedure utilizes double diffusion and electrophoresis principles. Immunoelectrophoresis procedure is used for identification of free κ and λ chains in paraprotein disease. Using specific anti-κ and anti-λ antisera, monoclonal nature of Bence Jones proteins in myeloma can be determined.
The largest amount of precipitate is found in the zone of equivalence where the number of multivalent sites of antigen and antibody are approximately equal
Rocket immunoelectrophoresis applies electrophoresis for facilitating migration of antigen in the agar. It is much more rapid than radial immunodiffusion (RID) and results can be obtained in a few hours. RID is modification of single diffusion method and takes more than 18 hours to obtain the results. Rocket immunoelectrophoresis is used for quantitative measurements of immunoglobulins, alpha-feto-protein in amniotic fluid, and complement components in body fluid
Western blot test is an adaptation of immunofixation electrophoresis technique and is used as confirmatory test to detect antibodies to HIV-1
Nephelometry can be used for quantitative measurements of immunoglobulins, complement components, haptoglobin, C-reactive protein, and other serum proteins
Which of the following is true of prozone phenomenon?
1 It occurs in the zone of equivalence
2 It occurs in the zone of antibody excess
3 It occurs in zone of antigen excess
4 It results in false positive reaction
5 It results in maximum precipitation
It occurs in the zone of antibody excess
Formation of precipitation is highly dependent on relative concentration of antigen and antibody. Prozone phenomenon results from antibody excess and can lead to false negative reaction. In prozone phenomenon, antigen combines with only one or two antibody molecules failing to form a cross-linkage. When false negative reaction due to prozone phenomenon is suspected, the test may be repeated after dilution of antibody.
Excess of antigen leads to postzone phenomenon and gives false negative reaction.
Largest amount of precipitate is found in the zone of equivalence where number of multivalent sites of antigen and antibody are approximately equal.
Classical pathway is mediated by
1 Antigen antibody complex
2 Viral envelopes
3 Capsular polysaccharide
4 Endotoxins
5 Teichoic acids
Antigen antibody complex
Alternate pathway is activated by bacterial capsular polysaccharide, endotoxin, teichoic acids, and viral envelopes.
Classical pathway is mediated by antigen antibody complexes. The classes of immunoglobulin that can trigger classical pathway include IgM, IgG1, IgG2, and IgG3.
The complement proteins involved in classical pathway include C1q, C1r, C1s, C4, C2, C3, C5, C6, C7, C8, and C9. A single molecule of IgM or two cross-linked molecules of IgG are required to fix the complement. Antigen antibody complex binds to C1q subunit via receptor in Fc region of antibody and activates the complement cascade.
The complement component/complex associated with bacterial cell lysis is
1 C1q
2 C3b
3 C4b2b
4 C5a
5 C5b6789
C5b6789
C5b6789 forms a membrane attack complex. Insertion of C5b6789 complex into cell membrane causes disruption of osmotic balance, resulting in lysis of bacteria cells, red blood cells, and tumor cells.
C1 is composed of 3 subunits C1q, C1r, and C1s. C1q is an aggregate of polypeptides that binds to receptor on Fc region of IgG or IgM, and classical pathway of the complement system is activated. C4b2b is C3 convertase and cleaves the C3 molecule into C3a and C3b. C3b is directly involved with opsonization of bacteria. C5a is a potent anaphylotoxin and a chemotactic factor.
Hereditary angioedema is caused by deficiency of
1 C1q
2 C3
3 C1 inhibitor
4 Decay accelerating factor
5 Hagman factor
C1 inhibitor
C1 inhibitor, or C1INH, is a glycoprotein that binds to C1q, causing dissociation of C1r and C1s, which leads to inhibition of further enzymatic activity. C1INH also inhibit components required for clot formation, such as activated Hagman factor, plasmin, kallikrein, and activated factor XI.
Hereditary angioedema is caused by deficiency of C1INH. It is inherited as an autosomal dominant gene that codes for dysfunctional protein or an inactive protein. One normal gene cannot produce sufficient C1INH to keep up with the demand. Hereditary angioedema is characterized by recurrent attacks of angioedema, which effect the extremities, the skin, oropharynx, and other mucosal surfaces. Reduced levels of C4 and C2 and normal levels of C1q and C3 are found in hereditary angioedema. C1q and C3 levels are decreased in acquired C1INH deficiency.
Deficiency of C1INH leads to excess cleavage of C2 and C4 and perpetuation of classical pathway. This triggers increased production of kinin-related protein, causing increased vascular permeability. Continued swelling and edema occurs in response to localized antigen stimulus.
B-cell differentiation factor that enhances IgA switching best describes which of the following cytokines?
1 Interleukin-2
2 Interleukin-3
3 Interleukin-5
4 Interleukin-7
5 Interleukin-8
6 Interleukin-10
7 Interleukin-13
Interleukin-5
Interleukins are a group of cytokines that are polypeptide products of activated cells. Interleukins control a variety of cellular responses and contribute in regulation of immune response.
Lymphokines are primarily produced by activated T cells. Interleukin-2 (IL-2) is a T cell growth factor secreted by antigen-stimulated T helper cells. IL-2 causes proliferation and clonal expansion of activated T cells. IL-2 also enhances proliferation of B cells and IgG2 antibody production by B cells. IL-2 assists in the clearing of any foreign antigen from the area by enhancing cytotoxicity of natural killer cells (NK cells).
Interleukin-3 (IL-3) is a lymphokine secreted by activated T cells and is a major immunologic mediator of myeloid differentiation. IL-3 serves as an important link between the immune system and the hematopoietic system. IL-3 causes proliferation of granulocytes and macrophages. IL-3 is also associated with regulation and differentiation of megacaryocytic, erythrocytic, and mast cell precursors.
Interleukin-5 (IL-5), also known as B-cell differentiation factor, is produced by activated T helper cells and mast cells. IL-5 causes proliferation of activated B cells and increased eosinophil production. IL-5 also enhances IgM secretion and class switching of IgA.
Interleukin-7 (IL-7) is a hematopoietic growth factor secreted by bone marrow stromal cells. IL-7 functions as a growth factor for both T cell and B cell precursors. IL-7 also enhances cytotoxic activity of lymphocytes and monocytes.
Interleukin-8 (IL-8) is an inflammatory cytokine secreted by monocytes and macrophages. IL-8 is chemotactic for both neutrophils and T cells. IL-8 causes activation of neutrophils to release lysosomal enzymes and leads to superoxide dismutase production that is lethal for pathogens.
Interleukin-10 (IL-10) is produced by activated T cells and mast cells. IL-10 inhibits cytokine synthesis and T cell proliferation in the presence of monocytes. In particular, IL-10 inhibits interleukin -2 and interferon-γ production by T helper cells. IL-10 enhances B cell differentiation, leading to increased antibody response.
Interleukin-13 (IL-13) is produced by T helper cells. IL-13 is an important regulator of inflammatory response because it inhibits activity and release of inflammatory cytokines by macrophages.
Inhibitor of inflammatory cytokines secreted by macrophages best describes which of the following cytokines?
1 Interleukin-2
2 Interleukin-3
3 Interleukin-5
4 Interleukin-7
5 Interleukin-8
6 Interleukin-10
7 Interleukin-13
Interleukin-13
Interleukins are a group of cytokines that are polypeptide products of activated cells. Interleukins control a variety of cellular responses and contribute in regulation of immune response.
Lymphokines are primarily produced by activated T cells. Interleukin-2 (IL-2) is a T cell growth factor secreted by antigen-stimulated T helper cells. IL-2 causes proliferation and clonal expansion of activated T cells. IL-2 also enhances proliferation of B cells and IgG2 antibody production by B cells. IL-2 assists in the clearing of any foreign antigen from the area by enhancing cytotoxicity of natural killer cells (NK cells).
Interleukin-3 (IL-3) is a lymphokine secreted by activated T cells and is a major immunologic mediator of myeloid differentiation. IL-3 serves as an important link between the immune system and the hematopoietic system. IL-3 causes proliferation of granulocytes and macrophages. IL-3 is also associated with regulation and differentiation of megacaryocytic, erythrocytic, and mast cell precursors.
Interleukin-5 (IL-5), also known as B-cell differentiation factor, is produced by activated T helper cells and mast cells. IL-5 causes proliferation of activated B cells and increased eosinophil production. IL-5 also enhances IgM secretion and class switching of IgA.
Interleukin-7 (IL-7) is a hematopoietic growth factor secreted by bone marrow stromal cells. IL-7 functions as a growth factor for both T cell and B cell precursors. IL-7 also enhances cytotoxic activity of lymphocytes and monocytes.
Interleukin-8 (IL-8) is an inflammatory cytokine secreted by monocytes and macrophages. IL-8 is chemotactic for both neutrophils and T cells. IL-8 causes activation of neutrophils to release lysosomal enzymes and leads to superoxide dismutase production that is lethal for pathogens.
Interleukin-10 (IL-10) is produced by activated T cells and mast cells. IL-10 inhibits cytokine synthesis and T cell proliferation in the presence of monocytes. In particular, IL-10 inhibits interleukin -2 and interferon-γ production by T helper cells. IL-10 enhances B cell differentiation, leading to increased antibody response.
Interleukin-13 (IL-13) is produced by T helper cells. IL-13 is an important regulator of inflammatory response because it inhibits activity and release of inflammatory cytokines by macrophages.
Cytokines produced by activated T cells and responsible for differentiation of hematopoietic stem cells and mast cells best describes which of the following cytokines?
1 Interleukin-2
2 Interleukin-3
3 Interleukin-5
4 Interleukin-7
5 Interleukin-8
6 Interleukin-10
7 Interleukin-13
Interleukin-3
Interleukins are a group of cytokines that are polypeptide products of activated cells. Interleukins control a variety of cellular responses and contribute in regulation of immune response.
Lymphokines are primarily produced by activated T cells. Interleukin-2 (IL-2) is a T cell growth factor secreted by antigen-stimulated T helper cells. IL-2 causes proliferation and clonal expansion of activated T cells. IL-2 also enhances proliferation of B cells and IgG2 antibody production by B cells. IL-2 assists in the clearing of any foreign antigen from the area by enhancing cytotoxicity of natural killer cells (NK cells).
Interleukin-3 (IL-3) is a lymphokine secreted by activated T cells and is a major immunologic mediator of myeloid differentiation. IL-3 serves as an important link between the immune system and the hematopoietic system. IL-3 causes proliferation of granulocytes and macrophages. IL-3 is also associated with regulation and differentiation of megacaryocytic, erythrocytic, and mast cell precursors.
Interleukin-5 (IL-5), also known as B-cell differentiation factor, is produced by activated T helper cells and mast cells. IL-5 causes proliferation of activated B cells and increased eosinophil production. IL-5 also enhances IgM secretion and class switching of IgA.
Interleukin-7 (IL-7) is a hematopoietic growth factor secreted by bone marrow stromal cells. IL-7 functions as a growth factor for both T cell and B cell precursors. IL-7 also enhances cytotoxic activity of lymphocytes and monocytes.
Interleukin-8 (IL-8) is an inflammatory cytokine secreted by monocytes and macrophages. IL-8 is chemotactic for both neutrophils and T cells. IL-8 causes activation of neutrophils to release lysosomal enzymes and leads to superoxide dismutase production that is lethal for pathogens.
Interleukin-10 (IL-10) is produced by activated T cells and mast cells. IL-10 inhibits cytokine synthesis and T cell proliferation in the presence of monocytes. In particular, IL-10 inhibits interleukin -2 and interferon-γ production by T helper cells. IL-10 enhances B cell differentiation, leading to increased antibody response.
Interleukin-13 (IL-13) is produced by T helper cells. IL-13 is an important regulator of inflammatory response because it inhibits activity and release of inflammatory cytokines by macrophages.
Lymphokine produced by antigen-stimulated T helper cells, causes proliferation of activated T and B cells and enhances toxicity of NK cells best describes which of the following cytokines?
1 Interleukin-2
2 Interleukin-3
3 Interleukin-5
4 Interleukin-7
5 Interleukin-8
6 Interleukin-10
7 Interleukin-13
Interleukin-2
Interleukins are a group of cytokines that are polypeptide products of activated cells. Interleukins control a variety of cellular responses and contribute in regulation of immune response.
Lymphokines are primarily produced by activated T cells. Interleukin-2 (IL-2) is a T cell growth factor secreted by antigen-stimulated T helper cells. IL-2 causes proliferation and clonal expansion of activated T cells. IL-2 also enhances proliferation of B cells and IgG2 antibody production by B cells. IL-2 assists in the clearing of any foreign antigen from the area by enhancing cytotoxicity of natural killer cells (NK cells).
Interleukin-3 (IL-3) is a lymphokine secreted by activated T cells and is a major immunologic mediator of myeloid differentiation. IL-3 serves as an important link between the immune system and the hematopoietic system. IL-3 causes proliferation of granulocytes and macrophages. IL-3 is also associated with regulation and differentiation of megacaryocytic, erythrocytic, and mast cell precursors.
Interleukin-5 (IL-5), also known as B-cell differentiation factor, is produced by activated T helper cells and mast cells. IL-5 causes proliferation of activated B cells and increased eosinophil production. IL-5 also enhances IgM secretion and class switching of IgA.
Interleukin-7 (IL-7) is a hematopoietic growth factor secreted by bone marrow stromal cells. IL-7 functions as a growth factor for both T cell and B cell precursors. IL-7 also enhances cytotoxic activity of lymphocytes and monocytes.
Interleukin-8 (IL-8) is an inflammatory cytokine secreted by monocytes and macrophages. IL-8 is chemotactic for both neutrophils and T cells. IL-8 causes activation of neutrophils to release lysosomal enzymes and leads to superoxide dismutase production that is lethal for pathogens.
Interleukin-10 (IL-10) is produced by activated T cells and mast cells. IL-10 inhibits cytokine synthesis and T cell proliferation in the presence of monocytes. In particular, IL-10 inhibits interleukin -2 and interferon-γ production by T helper cells. IL-10 enhances B cell differentiation, leading to increased antibody response.
Interleukin-13 (IL-13) is produced by T helper cells. IL-13 is an important regulator of inflammatory response because it inhibits activity and release of inflammatory cytokines by macrophages.
Neutrophil and T cell chemoattractant produced by monocytes and macrophages best describes which of the following cytokines?
1 Interleukin-2
2 Interleukin-3
3 Interleukin-5
4 Interleukin-7
5 Interleukin-8
6 Interleukin-10
7 Interleukin-13
Interleukin-8
Interleukins are a group of cytokines that are polypeptide products of activated cells. Interleukins control a variety of cellular responses and contribute in regulation of immune response.
Lymphokines are primarily produced by activated T cells. Interleukin-2 (IL-2) is a T cell growth factor secreted by antigen-stimulated T helper cells. IL-2 causes proliferation and clonal expansion of activated T cells. IL-2 also enhances proliferation of B cells and IgG2 antibody production by B cells. IL-2 assists in the clearing of any foreign antigen from the area by enhancing cytotoxicity of natural killer cells (NK cells).
Interleukin-3 (IL-3) is a lymphokine secreted by activated T cells and is a major immunologic mediator of myeloid differentiation. IL-3 serves as an important link between the immune system and the hematopoietic system. IL-3 causes proliferation of granulocytes and macrophages. IL-3 is also associated with regulation and differentiation of megacaryocytic, erythrocytic, and mast cell precursors.
Interleukin-5 (IL-5), also known as B-cell differentiation factor, is produced by activated T helper cells and mast cells. IL-5 causes proliferation of activated B cells and increased eosinophil production. IL-5 also enhances IgM secretion and class switching of IgA.
Interleukin-7 (IL-7) is a hematopoietic growth factor secreted by bone marrow stromal cells. IL-7 functions as a growth factor for both T cell and B cell precursors. IL-7 also enhances cytotoxic activity of lymphocytes and monocytes.
Interleukin-8 (IL-8) is an inflammatory cytokine secreted by monocytes and macrophages. IL-8 is chemotactic for both neutrophils and T cells. IL-8 causes activation of neutrophils to release lysosomal enzymes and leads to superoxide dismutase production that is lethal for pathogens.
Interleukin-10 (IL-10) is produced by activated T cells and mast cells. IL-10 inhibits cytokine synthesis and T cell proliferation in the presence of monocytes. In particular, IL-10 inhibits interleukin -2 and interferon-γ production by T helper cells. IL-10 enhances B cell differentiation, leading to increased antibody response.
Interleukin-13 (IL-13) is produced by T helper cells. IL-13 is an important regulator of inflammatory response because it inhibits activity and release of inflammatory cytokines by macrophages.
Hematopoietic growth factor secreted by bone marrow stromal cells, associated with proliferation of pre-B cells, pre-T cells, and mature T cells best describes which of the following cytokines?
1 Interleukin-2
2 Interleukin-3
3 Interleukin-5
4 Interleukin-7
5 Interleukin-8
6 Interleukin-10
7 Interleukin-13
Interleukin-7
Interleukins are a group of cytokines that are polypeptide products of activated cells. Interleukins control a variety of cellular responses and contribute in regulation of immune response.
Lymphokines are primarily produced by activated T cells. Interleukin-2 (IL-2) is a T cell growth factor secreted by antigen-stimulated T helper cells. IL-2 causes proliferation and clonal expansion of activated T cells. IL-2 also enhances proliferation of B cells and IgG2 antibody production by B cells. IL-2 assists in the clearing of any foreign antigen from the area by enhancing cytotoxicity of natural killer cells (NK cells).
Interleukin-3 (IL-3) is a lymphokine secreted by activated T cells and is a major immunologic mediator of myeloid differentiation. IL-3 serves as an important link between the immune system and the hematopoietic system. IL-3 causes proliferation of granulocytes and macrophages. IL-3 is also associated with regulation and differentiation of megacaryocytic, erythrocytic, and mast cell precursors.
Interleukin-5 (IL-5), also known as B-cell differentiation factor, is produced by activated T helper cells and mast cells. IL-5 causes proliferation of activated B cells and increased eosinophil production. IL-5 also enhances IgM secretion and class switching of IgA.
Interleukin-7 (IL-7) is a hematopoietic growth factor secreted by bone marrow stromal cells. IL-7 functions as a growth factor for both T cell and B cell precursors. IL-7 also enhances cytotoxic activity of lymphocytes and monocytes.
Interleukin-8 (IL-8) is an inflammatory cytokine secreted by monocytes and macrophages. IL-8 is chemotactic for both neutrophils and T cells. IL-8 causes activation of neutrophils to release lysosomal enzymes and leads to superoxide dismutase production that is lethal for pathogens.
Interleukin-10 (IL-10) is produced by activated T cells and mast cells. IL-10 inhibits cytokine synthesis and T cell proliferation in the presence of monocytes. In particular, IL-10 inhibits interleukin -2 and interferon-γ production by T helper cells. IL-10 enhances B cell differentiation, leading to increased antibody response.
Interleukin-13 (IL-13) is produced by T helper cells. IL-13 is an important regulator of inflammatory response because it inhibits activity and release of inflammatory cytokines by macrophages.
Which of the following is true of cytokines?
1 Tumor necrosis factors stimulate T cell proliferation
2 Tumor necrosis factor-α is secreted by macrophages
3 Tumor necrosis factor-β is secreted by bone marrow stromal cells
4 Interferon-β has antiviral activity and inhibits MHC class I expression
5 Transforming growth factor-β enhances B cell proliferation and suppresses secretion of inflammatory mediators
Tumor necrosis factor-α is secreted by macrophages
Tumor necrosis factors (TNF) possess many of the same activity as IL-1. TNF differs from IL-1 in that TNF are not able to stimulate T cell proliferation, and IL-1 has only limited ability to lyse tumor cells.
Tumor necrosis factor-α (TNF-α) is secreted by macrophages when stimulated by antigen. TNF-α is associated with production of hemorrhagic necrosis in tumors.
Tumor necrosis factor-β (TNF-β) is produced by T cells and B cells. TNF- β is responsible for killing tumor cells and virally infected cells.
Interferon-β inhibits synthesis of viral proteins by triggering the host cell to produce a second protein that interferes with the viral protein synthesis. Interferon-β is primarily secreted by fibroblasts and epithelial cells and enhances MHC class I expression.
Transforming growth factor-β (TGF-β) inhibits T and B cell proliferation. TGF-β is chemotactic for monocytes and induces secretion of inflammatory mediators.
T cells
1 Are thymus independent lymphocytes
2 Are responsible for cellular immune response
3 Lack antigen receptors on the cell surface
4 Differentiates into plasma cells
5 Consist of IgM on their surface
Are responsible for cellular immune response
T cells are thymus dependent lymphocytes as they mature in thymus. B cells are thymus independent lymphocytes that develops in the bursa of Fabricius. IgM is present on the surface of B cells and not T cell. Also B cells are associated with antibody production. B cells differentiates into plasma cells and memory cells. Specific antigen receptors are present on the cell surface of T cells and are involved in cell mediated immunity. T cells are associated with production of cytokines which include synthesis of IL-2, IL-4, IL-5 and gamma interferons.
Which of the following surface markers can be described as a surface antigen found on T helper cells?
1 CD2
2 CD3
3 CD4
4 CD8
5 CD19
CD4
Proteins found on cell surfaces can be used as markers to differentiate T cells and B cells. The maturation stages of the two types of cells can also be distinguished using these antigens or surface markers. CD (cluster of differentiation) classification is used as a reference in standardizing names of membrane proteins found on all human white cells.
CD2 is the earliest T-cell marker and is present on every peripheral T cells. It is also expressed by NK cells. CD2 is a receptor for sheep red blood cells. It demonstrates the rosetting phenomenon, in which sheep red blood cells adhere to CD2 receptor, encircling the T cells and forming a daisy pattern.
Mature T cells bearing the CD4 receptor are known as helper or inducer cells. CD4+ cells recognize antigens in association with MHC class II product.
The population of matured T cells that express CD8 antigens are T-cytotoxic cells. These cells provide primary line of defense against changed self antigen, especially virally infected cells and tumor cells. Direct cell contact can result in destruction of target cells without antibody involvement.
CD3 serves as T cell antigen receptor and is involved in signal transduction.
CD19 is found on B cells and acts as a co-receptor that assists in enhancing antibody production in mature B cells.
Which of the following surface markers can be described as a T cell receptor responsible for sheep red blood cell rosetting?
1 CD2
2 CD3
3 CD4
4 CD8
5 CD19
CD2
Proteins found on cell surfaces can be used as markers to differentiate T cells and B cells. The maturation stages of the two types of cells can also be distinguished using these antigens or surface markers. CD (cluster of differentiation) classification is used as a reference in standardizing names of membrane proteins found on all human white cells.
CD2 is the earliest T-cell marker and is present on every peripheral T cells. It is also expressed by NK cells. CD2 is a receptor for sheep red blood cells. It demonstrates the rosetting phenomenon, in which sheep red blood cells adhere to CD2 receptor, encircling the T cells and forming a daisy pattern.
Mature T cells bearing the CD4 receptor are known as helper or inducer cells. CD4+ cells recognize antigens in association with MHC class II product.
The population of matured T cells that express CD8 antigens are T-cytotoxic cells. These cells provide primary line of defense against changed self antigen, especially virally infected cells and tumor cells. Direct cell contact can result in destruction of target cells without antibody involvement.
CD3 serves as T cell antigen receptor and is involved in signal transduction.
CD19 is found on B cells and acts as a co-receptor that assists in enhancing antibody production in mature B cells.
Which of the following is a surface marker present primarily on T-cytotoxic cells and T-suppressor cells
1 CD2
2 CD3
3 CD4
4 CD8
5 CD19
CD8
Proteins found on cell surfaces can be used as markers to differentiate T cells and B cells. The maturation stages of the two types of cells can also be distinguished using these antigens or surface markers. CD (cluster of differentiation) classification is used as a reference in standardizing names of membrane proteins found on all human white cells.
CD2 is the earliest T-cell marker and is present on every peripheral T cells. It is also expressed by NK cells. CD2 is a receptor for sheep red blood cells. It demonstrates the rosetting phenomenon, in which sheep red blood cells adhere to CD2 receptor, encircling the T cells and forming a daisy pattern.
Mature T cells bearing the CD4 receptor are known as helper or inducer cells. CD4+ cells recognize antigens in association with MHC class II product.
The population of matured T cells that express CD8 antigens are T-cytotoxic cells. These cells provide primary line of defense against changed self antigen, especially virally infected cells and tumor cells. Direct cell contact can result in destruction of target cells without antibody involvement.
CD3 serves as T cell antigen receptor and is involved in signal transduction.
CD19 is found on B cells and acts as a co-receptor that assists in enhancing antibody production in mature B cells.
Which of the following is a surface marker associated with T cell antigen receptor and signal transduction?
1 CD2
2 CD3
3 CD4
4 CD8
5 CD19
CD3
Proteins found on cell surfaces can be used as markers to differentiate T cells and B cells. The maturation stages of the two types of cells can also be distinguished using these antigens or surface markers. CD (cluster of differentiation) classification is used as a reference in standardizing names of membrane proteins found on all human white cells.
CD2 is the earliest T-cell marker and is present on every peripheral T cells. It is also expressed by NK cells. CD2 is a receptor for sheep red blood cells. It demonstrates the rosetting phenomenon, in which sheep red blood cells adhere to CD2 receptor, encircling the T cells and forming a daisy pattern.
Mature T cells bearing the CD4 receptor are known as helper or inducer cells. CD4+ cells recognize antigens in association with MHC class II product.
The population of matured T cells that express CD8 antigens are T-cytotoxic cells. These cells provide primary line of defense against changed self antigen, especially virally infected cells and tumor cells. Direct cell contact can result in destruction of target cells without antibody involvement.
CD3 serves as T cell antigen receptor and is involved in signal transduction.
CD19 is found on B cells and acts as a co-receptor that assists in enhancing antibody production in mature B cells.
Refer to the diagram below. If a patient is unable to produce IgA isotype due to a selective IgA-chain deficiency, what region of the immunoglobulin is affected?
1 A
2 B
3 C
4 D
5 E
C
The correct response is C.
An immunoglobulin’s isotype is determined by the constant portion of the heavy chain gene, which on a protein level corresponds to all of the Fc and part of the Fab fragment.
Letter A demarcates the variable portion of the light chain protein.
Letter B demarcates the constant portion of the light chain protein.
Letter D demarcates the variable portion of the heavy chain protein.
Letter E demarcates the variable portion, or the idiotype, of the immunoglobulin.
