Immunology - Immune Responses Flashcards
Which cells secrete interleukin-1?
Macrophages
What are the effects of interleukin-1 secretion?
Acute inflammation; interleukin-1 induces recruitment of leukocytes, activates the endothelium to express adhesion molecules, and serves as an endogenous pyrogen
What are the effects of interleukin-2?
Interleukin-2 stimulates growth of helper and cytotoxic T cells
What are the functions of interleukin-3?
Growth and differentiation of stem cells in the bone marrow
Which cell type secretes interleukin-3?
Activated T cells
What are the functions of interleukin-4?
Promotion of B-cell growth and induction of class switching to immunoglobulin E and immunoglobulin G
What is the function of interleukin-5? By what type of cells is it secreted?
Interleukin-5 is involved in promotion of differentiation of B cells and induction of class switching to immunoglobulin A; it also stimulates production and activation of eosinophils; it is ecreted by Th2cells
What is the function of interleukin-6? By what cells is it produced?
Interleukin-6 stimulates production of acute-phase reactants and immunoglobulins; it is produced by helper T cells and macrophages
Which cytokine is a major chemotactic factor for neutrophils?
Interleukin-8
Which cell type secretes interleukin-8?
Macrophages
Which cytokine, released by regulatory T cells, inhibits actions of activated T cells?
Interleukin-10
What is the function of interleukin-12? Which cells secrete interleukin-12?
Interleukin-12 activates natural killer and Th1cells; it is secreted by B cells and macrophages
What cytokine that is secreted by Th1 cells stimulates macrophages?
γ-Interferon
Which cytokine, secreted by macrophages, is an important mediator of septic shock?
Tumor necrosis factor
What are the effects of tumor necrosis factor secretion? By which cells is tumor necrosis factor secreted?
Tumor necrosis factor mediates leukocyte recruitment and vascular leak; it is secreted by macrophages
Which cytokine stimulates bone marrow?
Interleukin-3
Which cell surface proteins are found on helper T cells?
CD4, TCR, CD3, CD23, CD40L
Which cell surface proteins are found on cytotoxic T cells?
CD8, TCR, CD3
Which cell surface proteins are found on B cells?
IgM, CD19, CD20, CD21, CD40, MHCII, B7
Which cell surface proteins are found on macrophages?
MHCII, B7, CD40, CD14, receptors for Fc and C3b
Which cell surface proteins are found on natural killer cells?
Receptors for MHC I, CD16, CD56
True or False? All human cells have major histocompatibility complex I.
False; mature red blood cells do not have major histocompatibility complex I
Which two types of immunoglobulins activate complement via the classic pathway?
Immunoglobulin G and Immunoglobulin M
What triggers the activation of complement via the alternative pathway?
Microbial surfaces (especially endotoxin)
What triggers the activation of complement via the classic pathway?
Antigen-antibody complexes
What triggers the activation of complement via the lectin pathway?
Microbial surfaces
In the complement system, the plasma proteins C1, C2, C3, and C4 are important for the neutralization of what types of infectious agents?
Viruses
The membrane attack complex of complement is especially important in the defense against what type of bacteria?
Gram-negative bacteria
In the complement system, what is the function of the plasma protein C3b?
Opsonization
In the complement system, the activation of what two plasma proteins can cause anaphylaxis?
C3a and C5a
Which complement protein is responsible for neutrophil chemotaxis?
C5a
In the complement system, the membrane attack complex performs what function?
Cytolysis of target antigen
The membrane attack complex is composed of which complement proteins?
C5b, C6, C7, C8, and C9
The deficiency of what plasma protein leads to overactive complement and hereditary angioedema?
C1 esterase inhibitor
What are the clinical sequelae of hereditary complement C3 deficiency?
Recurrent pyogenic sinus and respiratory tract infections
In the complement system, the deficiency of which plasma proteins can predispose someone to Neisseriabacteremia?
C5-C8
In the complement system, the deficiency of which plasma protein leads to paroxysmal nocturnal hemoglobinuria?
Decay-accelerating factor
True or False? Decay accelerating factor and C1 esterase inhibitor help prevent complement activation on host cells.
True
In the complement system, the cleavage of which plasma protein is the first shared step for both the alternative and classic pathways?
C5
What is the name for the complex of MC5b, 6, 7, 8, and 9 in the final step of the complement system, which lyses target cells?
Membrane attack complex
What are the two primary opsonins used to defend against bacteria?
C3b and immunoglobulin G
Name the class of plasma proteins secreted to place uninfected cells in an antiviral state and that inhibit viral protein synthesis.
Interferons
Name three mechanisms by which interferons interfere with viral protein synthesis.
Interferons induce viral mRNA-destroying proteins, increase major histocompatibility complex I and II expression, and activate natural killer cells to kill virus-infected cells
Which interferons increase major histocompatibility complex I and II expression and antigen presentation in all cells?
γ-Interferon
Which interferons inhibit viral protein synthesis?
a-Interferon and b-interferon induce production of ribonucleases that inhibit viral protein synthesis
Which cytokines activate natural killer cells to kill virus-infected cells?
Interferons
Interferons activate _____ (natural killer cells/macrophages) to kill virus-infected cells.
Natural killer cells
How does active immunity differ from passive immunity?
In active immunity, the host forms antibodies; in passive immunity, the host receives preformed antibodies
Give four examples of diseases for which preformed antibodies are given after exposure.
Tetanus, botulism, hepatitis B, and rabies (remember: To Be Healed Rapidly)
What is the approximate half-life of antibodies transferred from one host to another in passive immunity?
3 weeks
Which antigen in breast milk confers passive immunity to newborns?
Immunoglobulin A
Antigenic _____ (drift/shift) is the natural mutation over time of known strains of influenza to evade the immune system.
Drift; this is the source of the annual influenza epidemics
Antigenic _____ (drift/shift) is the process by which two strains of influenza combine to form a new subtype that has a mixture of the surface antigens of the two original strains.
Shift; this is the source of worldwide influenza pandemics such as the 2009 H1N1 flu
In what way does Salmonellabacteria exhibit antigenic variation?
Via flagellar variants
In what way does Neisseria gonorrhea exhibit antigenic variation?
Pilus protein variation
In what way does influenza demonstrate antigenic variation?
RNA shifts and drifts
In what way do trypanosomes demonstrate antigenic variation?
Programmed rearrangement
Describe the process of T-cell anergy.
Self-reactive T cells become nonreactive when they do not receive a costimulatory molecule
True or False? Both B cells and T cells can develop anergy to self-antigens, but B cells display more complete tolerance.
False; tolerance to self-antigens is greater in T cells than in B cells
List four bacterial infections that can cause granulomatous disease
Tuberculosis, syphilis, leprosy, and cat scratch fever
What are three noninfectious conditions associated with granulomatous disease?
Sarcoidosis, Crohn;s disease, berylliosis
Name the four cell types found in granulomas.
Epithelioid cells and giant cells are specialized macrophages; fibroblasts and lymphocytes are also found in granulomas
Which type of hypersensitivity reaction involves antigen cross-linking immunoglobulin E on mast cells and basophils, triggering the release of histamine?
Type 1
Which type of hypersensitivity reaction develops rapidly after antigen exposure as a result of preformed antibody?
Type 1
Which type of hypersensitivity reaction involves immunoglobulin M and immunoglobulin G binding to the body;s own cells, thereby leading to lysis by complement or phagocytosis?
Type 2
Which type of hypersensitivity reaction causes fever, urticaria, arthralgias, proteinuria, and lymphadenopathy 5 to 10 days after antigen exposure?
Serum sickness (a type 3 hypersensitivity reaction)
Which type of hypersensitivity reaction is caused by immune complexes that activate complement and attract neutrophils that release lysosomal enzymes?
Type 3
Which type of hypersensitivity reaction is the Arthus reaction?
Type 3
What is the Arthus reaction?
An immune complex disease (type III hypersensitivity) in which antibodies to foreign proteins are produced and deposited in tissues where they fix complement and lead to tissue damage
What are the signs and symptoms of serum sickness?
Fever, urticaria, arthralgias, proteinuria and lymphadenopathy
How long does it take after exposure to antigen for the fever, urticaria, and arthralgias characteristic of serum sickness to develop?
5-10 days
What is the cause of most cases of serum sickness?
Drugs
What two components make up the immune complexes that cause type III hypersensitivity reactions?
Antigens and antibodies; antigen-antibody complexes activate complement to cause tissue damage
What type III sensitivity reaction is characterized by local edema, necrosis, and the activation of complement?
Arthus reaction