Exam 3 Practice Set 2 Flashcards
Extracellular bacteria are optimally killed by:
A Macrophages.
B Complement.
C Antibody.
D Macrophages plus complement.
E Macrophages plus antibody plus complement.
E Macrophages plus antibody plus complement.
Opsonization of bacteria occurs through coating bacteria just with: A C3b B C8 C Membrane attack complex D F(ab')2 IgG E IgM
A C3b
Extracellular bacteria try to avoid killing by:
A Activating neutrophils.
B Accelerating complement activation.
C Synthesizing capsules.
D By deviating complement deposition to the cell membrane.
E Limiting variation in their antigens.
D By deviating complement deposition to the cell membrane.
CR1 complement receptors on phagocytic cells bind: A Factor H B Factor I C C3d D Only inactive C3b (iC3b) E C3b
E C3b
iC3b binds to: A Factor H B C5 convertase C CR1 D CR2 E C3 convertase
C CR1
Individuals lacking C8 or C9 are more prone to infection with the following type of bacteria: A Haemophilus influenzae. B Bacillusanthrax. C Vibrio cholerae. D Neisseria. E Listeria monocytogenes.
D Neisseria.
Ideally, the membrane attack complex generated by complement activation lyses bacteria, especially Neisseria species that are particularly susceptible to lysis because of their thin cell walls, and complement byproducts stimulate inflammatory responses by recruiting and activating leukocytes.
Neutrophil chemotaxis is mediated by: A. C5b B. IL-8 C. C3a D. CCL2 E. E-selectin
B. IL-8
The membrane attack complex consists of: A OH B Colicins C C3b3b, Bb D C5b,6,7,8,9 E Properdin
D C5b,6,7,8,9
C3b: A Is chemotactic. B Is an anaphylatoxin. C Opsonizes bacteria. D Directly injures bacteria. E Is the inactive form of C3.
C Opsonizes bacteria.
IgG antibodies:
A Are the earliest class to appear in an immune response.
B Are normally dimeric in mucosal secretions.
C Remain of low affinity.
D Inhibit antibody responses through the Fc gamma receptor FcgRIIB1 on B-cells.
E Augment antibody responses through the Fc gamma receptor FcgRIIB1 on B-cells.
D Inhibit antibody responses through the Fc gamma receptor FcgRIIB1 on B-cells.
Dendritic cells can be driven from a resting state to an activated state by the T-cell surface molecule: A TCR B CD40L C CD28 D B7 E CD40
B CD40L
Which is the first of the following genes to be upregulated subsequent to T-cell activation: A Transferrin receptor B Cytokine receptor C Cytokine D c-Myc E VLA-1
D c-Myc
Cytokines always act: A By binding to specific receptors. B In an autocrine fashion. C At long range. D Antagonistically with other cytokines E Synergistically with other cytokines
A By binding to specific receptors.
A cytokine receptor which is a member of the hematopoietic receptor family is: A IL-8 receptor B IFN gamma receptor C TNF (TNF-alpha) receptor D IL-1 receptor E IL-2 receptor
E IL-2 receptor
IFN-gamma and TNF (TNF alpha) can act synergistically:
A To downregulate expression of MHC class I
B Because IFN-gamma downregulates expression of TNF receptors
C To upregulate expression of MHC class II
D Because they both bind to the same receptor
E Because they cross-link IFN-gamma and TNF beta receptors
C To upregulate expression of MHC class II
Which of the following is characteristically produced by the Th2 CD4 cells which provide help for antibody production, but not by Th1 cells? A IFN-gamma B Lymphotoxin (TNF-beta) C GM-CSF D IL-4 E IL-1
D IL-4
In the germinal center, B-cells become memory cells under the influence of: A CD40 B CD23 C IL-1 alpha D IL-4 E TGF beta
A CD40
High affinity B-cell clones in mammals are usually generated by:
A Somatic hypermutation
B Expression of high affinity precursors in the virgin (naive) B-cell population
C Class switching
D Apoptosis
E Gene conversion
A Somatic hypermutation
Prior to class switching, B-cells express: A IgA alone B IgA and IgG C IgM and IgD D IgD alone E No surface Ig
C IgM and IgD
The specificity of antibody secreted by a B-cell may not be the same as that of the surface Ig of the clonal parent because of: A Class switching B Somatic hypermutation C Allelic exclusion D Alternative splicing E Different heavy:light pairing
B Somatic hypermutation
In the thymic medulla, the majority of gamma delta T-cells are: A CD4+CD8+ B CD4+CD8- C CD4-CD8+ D CD4-CD8- E Surface Ig+
D CD4-CD8-
The major long term source of a foreign antigen in the body is:
A Anti-idiotype
B Complexes on the surface of follicular dendritic cells
C Antigen bound to the surface of B-cells
D Antigenic peptides in the groove of MHC molecules
E There are no long term sources of foreign antigen in the body
B Complexes on the surface of follicular dendritic cells
Cytokines:
A Are usually around 150-200 kDa
B Have glycosyl phosphatidylinositol (GPI) anchors
C Can be pleiotropic
D Generally act at long range
E Produce very stable long-lived messenger RNA
C Can be pleiotropic
Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits. Consequently, a mutation in a pleiotropic gene may have an effect on some or all traits simultaneously. An example is phenylketonuria, a human disease that affects multiple systems but is caused by one gene defect. (Wikipedia)
Th1 cell secrete: A CD4 B IL-4 C IL-5 D IL-6 E IFN-gamma
E IFN-gamma
Which one of the following cytokines can mediate release of acute phase proteins from the liver? A IL-10 B TGF-beta C IL-6 D IL-12 E IL-8
C IL-6
Which of the following is not a feature of germinal center B-cells: A Immunoglobulin gene class switching B Apoptosis C Initial VDJ rearrangement D Somatic hypermutation E Proliferation
C Initial VDJ rearrangement
Low amounts of antigen:
A Produce low affinity antibodies
B Do not influence the affinity of antibodies
C Produce high affinity antibodies
D Affect the avidity but not the affinity of antibodies
E Preferentially induce class switching
C Produce high affinity antibodies
Because the BCR recognizes an epitope of the native protein with high affinity, specific B cells bind and present the antigen much more efficiently (i.e., at much lower concentrations) than do other B cells not specific for the antigen. This is why B cells specific for an antigen respond preferentially to that antigen, compared with other cells.
The level of antigen:
A Is unrelated to the intensity of the immune response
B Is related to the intensity of the immune response
C Never has an effect on the response to a T-independent antigen
D Has no effect on the concentration of MHC bound processed antigen
E Is constant in the extracellular fluid
B Is related to the intensity of the immune response
Memory T-cells:
A Are continuously produced directly from naive progenitors
B Express high levels of CD44
C Are only present in primary immune responses
D Switch from an alpha beta to gamma delta T cell receptor
E. Express germ line Ig V genes
B Express high levels of CD44