Exam I Flashcards
Define vaccination.
any procedure of injecting immunogenic material into the body in order to induce immunity
Define chemotaxis.
movement towards a stimulus, particularly that movement displayed by phagocytic cells toward bacteria and sites of cell injury
Define immunology.
the study of reactions (immune response) of a host when foreign substances are introduced into the body
Define opsonin.
a substance in serum that promotes immune adherence and facilitates phagocytosis by the reticuloendothelial (RE) system
Define antibodies.
protein substances secreted by plasma cells developed in response to and specifically for an antigen
Define nonsusceptibility.
absolute protection against particular diseases associated with species characteristics
Define natural immunity.
ability of the individual to resist infection by means of normally present body functions
Define immunity.
the condition of being resistant to an infection
Define serology.
study of the noncellular portion of the blood known as serum
Define phagocytosis.
ingestion of microorganisms, other cells, and foreign particles by a phagocyte (leukocytes, macrophages, etc.)
Define antigen.
substance recognized by the body as being foreign, which can cause an immune response
Define active immunity and give an example.
active formation of specific antibody by the host induced by exposure to an infectious agent or to one of the agent’s antigens; usually the result of a natural infection or a vaccination
Define passive immunity and give an example.
results from injection of antibodies derived from another individual; it is more transient, lasting only a few weeks or months; can be acquired in utero from maternal circulation, post-partum via mother’s milk, and through IV immunoglobulin
Define adoptive immunity and give an example.
produced by transfer of antigen-sensitive lymphocytes from an actively immunized donor to an immunocompromised recipient
What are the four types of opsonins?
C-reactive protein (CRP), antibodies, complement components, mannose-binding protein (MBP)
Define lymphokines.
cytokines produced by lymphocytes; the end product of T-cell antigen recognition that regulates the function of other cells and tissues
What is an adjuvant?
substance administered with an antigen that increases the immune response by extending the period of antigen exposure
Define immune tolerance.
lack of an immune response or an active immunosuppressive response due to repeated exposure to the antigens
Where are T-cells modified and what type of immunity are they responsible for?
modified in the thymus, responsible for cellular immunity
Where are B-cells modified and what type of immunity are they responsible for?
modified in the bone marrow, responsible for humoral immunity
Which type of cell, T- or B-, is the predominant type of lymphocyte in the blood?
T-cells
What are the three types of T-cells?
T-effector (T-cytotoxic), T-helper (T-inducer), T-regulatoryt
Which cells differentiate into plasma cells and what do they secrete?
B-cells, secrete antibody
Describe primary immune response, including which immunoglobulins are produced.
primary antibody response on initial antigen encounter; IgM detected after 3-4 days
Describe secondary (anamnestic) response, including which immunoglobulins are produced.
occurs 1-2 weeks after exposure, period of time when IgM peaks, plateaus, and then begins to decrease; IgG is produced, and remains at a higher level for a longer period of time
What is the role of memory cells?
a special type of long-lived, rapidly-activated B-cells that carry immunological memory to a specific antigen, which provides long-term protection against that specific disease
Name the immunodeficiency disease in which a decrease of IgG results in a greater susceptibility to infection.
acquired agammaglobulinemia
Briefly describe what happens in multiple myeloma, including which immunoglobulin is overproduced.
consists of plasma cell tumors in the bone marrow that overproduce a single class of immunoglobulin; 50-60% of cases are IgG monoclonal gammopathy
Which fragment of an immunoglobulin molecule directs biological activity?
constant region (Fc fragment)
Which fragment of an immunoglobulin molecule possesses antigen binding ability?
variable region (Fab fragment)
An immunoglobulin light chain will occur as either one of these two types, but never both.
kappa or lambda
Define epitope, including its alternate name.
also known as determinant site; the part of the antigen that is actually recognized in an immune response
What molecular weight does an antigen have to be in order to be recognized?
> /= 10,000 Daltons
List the proper sequence of the complement cascade in the classical pathway, including when calcium and magnesium are added.
C1 (Ca2+ added), C4 (Mg2+ added), C2, C3, C5, C6, C7, C8, C9
What is meant by the properdin pathway?
properdin is a protein in the alternative complement pathway; stabilizes the C3 convertase formed from the activation of other factors
Which complement component is cytolytic?
C8
Which complement component accelerates the process for rapid lysis?
C9
Name and describe the functions and characteristics of IgG.
associated with secondary (anamnestic) response; highest concentration in adults (~75%), most important; 23-25 day half-life; compose most bacterial, virus neutralizing, and precipitating antibodies, hemagglutinins, and hemolysins; 4 subclasses - 1-3 fix complement, 4 does not; ONLY immunoglobulin that can cross the placenta, provides immunity for the newborn; capable of opsonization; activates complement (2 molecules needed)
Name and describe the functions and characteristics of IgM.
largest of the immunoglobulins; 10-day half life; five basic structural units in circular arrangement (pentameter); 5-10% of all anitbody; flexible - can assume many shapes; first to appear in primary response; first produced by infants; IgM decreases as IgG increases; most often formed against Gram= bacteria, also makes up heterophile antibody, rheumatoid factor, cold agglutinins, and hemagglutinins; activates complement (1 molecule needed); 2 subclasses; neutralizes toxins and opsonins
Name and describe the functions and characteristics of IgA.
main immunoglobulin in various secretions (saliva, tears, sweat, breast milk, respiratory, intestinal, and genital secretions), “secretory IgA”; binds antigen at portals of entry to prevent their adherence and invasion; confers immunity from mother to child (breast milk); 2 subclasses - IgA2 is predominant; does NOT fix complement
Name and describe the functions and characteristics of IgE.
lowest concentration (0.0005%); has an extra domain capable of binding with receptors on mast cells and basophils; interaction with mast cells stimulates allergic reactions to convert from life threatening anaphylaxis to milder allergy symptoms; thought to play a role in the defense against parasitic infections by recruiting eosinophils when there are antigens too large to be phagocytized; elevated in the serum of patients with parasitic infections or Type I allergic disorders/reactions; formed by tissues of the respiratory and GI tracts; does NOT fix complement; also called reagin (NOT the same as syphillis reagin); no agglutination or opsonization used to be qualified with the RAST test, which is now obsolete
Name and describe the functions and characteristics of IgD.
low concentration (0.001%); discovered in 1965 in a multiple myeloma patient; most present on the surface of immunocompetent but unstimulated B-lymphs; second immunoglobulin to appear, and may play a role, in B-cell activation, maturation, and differentiation; elevated in certain autoimmune disease; 2-3 day half life; does NOT bind complement
What are the two classes of immunoglobulin that can “fix” complement?
IgG and IgM
Which complement components are bypassed in the alternate pathway?
C1, C4, C2
What is the third complement pathway called, is it antibody dependent, and what is its major constituent?
lectin pathway; antibody independent; major constituent is mannose-binding lectin (MBL)
Which element holds together the C1 complement component?
calcium (Ca2+)
Which element is required for C2 complement component to become involved in the cascade?
magnesium (Mg2+)
Which complement component is the most abundant?
C3
Describe natural killer cells.
cytolytic cells with no T- or B-cell markers (null cells)
How many Fc fragments are needed to activate complement?
2
What are two ways to inactivate complement in a serum sample?
heat to 56*C; age for a few weeks
What are heterophile antigens?
antigens that are possessed by a variety of different phylogenetically unrelated species
What are HLA antigens and what is the system of genes that control their expression?
Human Leukocyte Antigen; any of several members of a system consisting of the gene products of at least four linked loci (A, B, C, and D) and a number of subloci on the sixth human chromosome that have been shown to have a strong influence on human allotransplantation, transfusions in refractory patients, and some disease associations; controlled by the Major Histocompatibility Complex (MHC)
Describe Waldenstrom’s macroglobulinemia.
non-Hodgkin’s lymphoma type that affects B-cells; characterized by increased production of macroglobulins (including cryoglobulins) giving rise to cold sensitivity; disease of the elderly, most often occurring between the ages of 60 and 70
Define haptens.
nonimmungenic materials that, when combined with a carrier, create new antigenic determinants; too small to be recognized on their own, so they complex with larger molecules to stimulate a response
Describe Jenner’s first contribution to immunology, including the phenomenon it demonstrated.
Jenner noticed that people who had been infected with cowpox were spared from smallpox epidemics. He inoculated a boy with cowpox pus, and once he recovered from cowpox he was inoculated with smallpox pus. The boy did not contract smallpox, even after the procedure was repeated several times. This demonstrated the phenomenon of cross immunity.
Metchnikoff is known for first describing what process in the immune response?`
phagocytosis
Describe Pasteur’s work with the first attenuated vaccine.
Pasteur accidentally discovered that old cultures would not cause cholera in chickens, and subsequent injections of more virulent organisms had no effect on birds who were previously exposed to these old cultures. It demonstrated that old cultures lose virulence but retain the ability to elicit immunity.
What six characteristics allow the body to use natural immunity?
lactic acid, hydrochloric acid, lysosomes, normal flora, cilia movement, and skin
Describe the process of inflammation.
blood supply to the affected area increases; capillary permeability increases, caused by the retraction of endothelial cells living in the vessels; white cells, mainly neutrophils, migrate from the capillaries to the surrounding tissue; macrophages migrate to the injured area
What is a phagolysosome, and at what point in phagocytosis is it formed?
the result of a phagosome fusing with cytoplasmic granules, which enables it to digest foreign particles and release debris to the outside; this is the third step in phagocytosis
Which of the white cells is capable of further differentiation in the tissues?
monocytes (they become macrophages)
Which of the white cells is the primary agent in the defense of the body against parasitic infection?
eosinophils
Which of the white cells is the primary agent against bacterial infection?
neutrophils
Which of the white cells is the primary agent against viral infection?
lymphocytes
How does normal flora function as a defense mechanism for the body?
competes with pathogens for nutrients
What area in humans is considered to be the equivalent of the bursa of Fabricius in birds?
bone marrow
Sheep red cells demonstrate rosetting due to which T-cell receptor?
CD2
Which well-known acute phase reactant is a non-specific indicator of inflammation and is known to appear before antibodies?
C-reactive protein (CRP)
Which class of cells does the Epstein-Barr virus selectively invade?
B-cells
The CD4 antigen is found on which subset of T cells?
helper cells
