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Pattern recognition receptors (PRR) can be found on
(A) B cells
(B) T cells
(C) Dendritic cells
(D) Defensins
C. Pattern recognition receptors for PAMP occur on host phagocytic cells.
Depressed levels of MHC class I molecules on virus infected host
cells can be detected by
(A) T cytotoxic cells
D. Depressed levels of MHC class I molecules are recognized by
(B) T suppressor cells
killer activated receptors on NK cells.
(C) Activated macrophages
(D) NK cells
Pathogen-associated molecular patterns
(A) Are found on many microorganisms
(B) Are restricted to Gram-positive bacteria
(C) Are restricted to Gram-negative bacteria
(D) Are restricted to toxin-secreting bacteria
A. PAMP are not restricted but are found on many microorganisms
but absent in humans. Binding by PRR initiates aspects of innate
immunity.
Cytokines
(A) Are specific, each with a single activity
(B) Can be blocked by extra-cytoplasmic portions of their cellular B. Multiple activities can be stimulated by a single cytokine, and a
receptor
single activity can be elicited by multiple cytokines.
(C) Release is restricted to lymphocytes
(D) Enter cells by a glucose transport system
The adaptive immune system develops from stem cells originating
in the
(A) Fetal thymus
B. Stem cells that evolve into cells of the adaptive immune system
(B) Fetal liver and bone marrow
originate in the fetal liver and bone marrow.
(C) Placenta
(D) Germinal centers of the spleen
Toll receptors
(A) Recognize PAMPS on selective microorganisms
(B) Link to IgM on B-cell surfaces
(C) Link to the antigen receptor on T cells
(D) Down-regulate inflammation
A. Toll-like receptors in the host bind to PAMPS on various microorganisms and trigger the activation of components of innate
immunity and early elimination of the infecting microorganism.
Group-specific streptococcal antigens are
(A) Carbohydrates
(B) Proteins
(C) Toxic
(D) Enzymatic
A. Group-specific streptococcal antigens are carbohydrates.
Antibodies are grouped into five classes based on differences in
their
C. A short sequence of amino acids is shared on the heavy chain of
(A) Kappa chains
each, thus permitting their classification together as immunoglob(B) Lambda chains
ulins.
(C) Heavy chains
(D) Light chains
Immunoglobulin isotypes are genetic variations found
(A) Only in transplant patients undergoing graft rejection
(B) Only in patients exhibiting graft-versus-host reactions
(C) Only in patients receiving blood transfusions
(D) In all normal humans
D. Isotypic variations among the immunoglobulins occurs in all
humans and is exemplified by the kappa and lambda chains.
All five antibody classes are grouped together as immunoglobulins
due to a
(A) Common amino acid sequence on the heavy chain
(B) Common amino acid sequence on the L chain
(C) Common amino acid sequence on the hinge region
(D) Common disulfide bond
B. Although antibodies are grouped into five classes based on
differences in their heavy chains, they are grouped together as
immunoglobulins because each has a common amino acid sequence on its light chain.
The killer inhibition receptor (KIR) on NK cells detects
(A) Gram-positive bacteria
(B) Gram-negative bacteria
C. KIR docks onto cells with normal levels of MHC class I molecules (in contrast to KAR, which detects cells with low levels
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(C) Cells with normal levels of MHC class I
(D) Cells with low levels of MHC class 1
of MHC class I molecules), thus preventing killing of normal,
uninfected cells.
The antibody idiotype refers to the
(A) Hypervariable region of the light chain
(B) Hypervariable region of the heavy chain
(C) Hypervariable region of both the heavy and light chains
(D) Complement binding region on the heavy chain
C. The antibody idiotype defines the epitope binding structure
comprised of both the heavy and light chain hypervariable regions.
Genetic control of heavy chain synthesis involves
(A) The variable region coded by three different gene complexes
(B) A J region gene linking first to a D region gene and then to a D. Each of the statements depicts genetic control of heavy chain
V region gene
synthesis.
(C) A VDJ complex linking to a mu region gene
(D) Each of the above
The T-cell antigenic receptor
(A) Is a monomeric IgM molecule
D. The T-cell antigenic receptor requires the antigenic determinant
(B) Is a monomeric IgG molecule
group to be processed and presented together with an HLA mol(C) Will respond only to epitopes processed by class I HLA molecule and does not respond directly to circulating antigen.
ecules
(D) Does not interact directly with circulating antigens
The Coombs direct test
(A) Detects nonagglutinating anti-Rh antibody on infants red blood
cells
A. The Coombs direct test detects nonagglutinating anti-Rh anti(B) Detects nonagglutinating anti-Rh antibody in maternal circubody on infants' red blood cells. The Coombs indirect test detects
lation
the anti-Rh antibody on maternal red blood cells.
(C) Measures cold agglutinins in primary atypical pneumonia
patients
(D) Measures serum complement levels
When only one of two parental alleles is expressed by a single B
cell, it is termed
B. The expression of only one parental allele by a B cell is termed
(A) Self-MHC restriction
allelic exclusion. Self-MHC restriction refers to the restriction of
(B) Allelic exclusion
antigen presentation only to HLAs of the same type.
(C) Random selection
(D) Haplotype exclusion
Which of these statements is incorrect
(A) Apoptosis is characterized by membrane blebbing and DNA
fragmentation
C. Th1 cells secrete those cytokines functional in cell-mediated
(B) Th2 cell cytokines induce B-cell transformation and prolifera- immunity, whereas IL-4, IL-5, and IL-6 are cytokines active in
tion
humoral immunity.
(C) Th1 cells secrete IL-4, IL-5, and IL-6
(D) Most fetal thymocytes die before leaving the thymus
Circulating antigen-antibody complexes pathogenic in lupus
glomerulonephritis
(A) Have antigen in excess
(B) Have antibody in excess
(C) Have antigen and antibody in equivalent amounts
(D) Do not interact with complement
A. The preponderance of self-antigens in patients with lupus
glomerulonephritis results in most of the complexes having antigen in excess.
Which of the following statements is incorrect
(A) T cytotoxic cells have the CD8 phenotype
(B) IL-1 and TNF-a induce selectins on the endothelial cell surface
C. IL-4, IL-10, and TGF-b help to reduce excessive inflammation,
(C) IL-4, IL-10, and TGF-b are main causes of excessive inflamnot cause it.
mation
(D) NK cells can express antibody dependent cellular cytotoxicity
(ADCC)
A major marker retained on all peripheral T cells is
(A) CD3
(B) CD4
(C) CD8
(D) IL-1
A. CD3 is retained on all peripheral T cells and serves as a marker
for total T-cell enumeration.
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CD34 is a marker for
(A) B cells
(B) Th2 cells
(C) The gamma delta T-cell receptor
(D) Stem cells
D. CD34 is a marker for stem cells and permits their isolation.
Tolerance to self-antigens can be achieved by
(A) Clonal deletion
(B) Clonal anergy
(C) High doses of antigen
(D) Low doses of antigen
(E) Each of the above
E. Different states of tolerance can be achieved by each of those
listed.
Which of the following statements is incorrect
(A) dsDNA-anti-dsDNA complexes can initiate glomerulonephritis
(B) Contact dermatitis due to poison ivy is an antigen-antibody
B. Contact dermatitis is a lesion of cell-mediated immunity, not
complex disease
union with antibody.
(C) Macrophages are activated nonspecifically by IFN-g
(D) Cross-linkage by antigen of two or more IgE molecules causes
degranulation of sensitized mast cells
Which of the following statements concerning AIDS is incorrect
(A) The Western blot test is the initial diagnostic test
(B) Both CD4+ T cells and macrophages can be infected
A. The Western blot is a confirmatory test for AIDS. Low CD4 levels
(C) HIV requires both CD4 and a chemokine coreceptor to enter are an initial alert.
cells
(D) HIV reverse transcriptase changes viral RNA into DNA
Multiple branched lipopolysaccharides on Gram-negative bacteria
(A) Inhibit B cells
B. Lipopolysaccharides of Gram-negative bacteria are thymus-in(B) Are thymus independent antigens
dependent antigens.
(C) Are nonantigenic
(D) Are haptens
Eradication of Mycobacterium tuberculosis would be largely dependent on
(A) NK cells
C. Tuberculosis eradication is an example of cell-mediated immu(B) Anti-M. tuberculosis antibodies
nity.
(C) T cytotoxic cells
(D) Dendritic cells
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