Exam 3 Practice Set 3

Question 1

Immunoglobulin classes must be distinguished by the type of:
A. light chains they possess.
B. carbohydrate on their light chains.
C. constant regions in their light chains.
D. heavy chains they possess.
E. none of the above.

Answer 1

D. heavy chains they possess.

Question 2

The variable regions in the light chains participate in:
A. Fc receptor binding.
B. epitope binding.
C. affinity of the complement receptors.
D. interaction of the Fab with cytokines.
E. none of the above.

Answer 2

B. epitope binding.

Question 3

J-chains are associated with:
A. IgG.
B. polymeric immunoglobulins.
C. serum IgA
D. IgE.
E. none of the above.

Answer 3

B. polymeric immunoglobulins.

Question 4

Adoptive-acquired immunity may be the result of:
A. transfer of bone marrow from one individual to another.
B. immunization with a vaccine.
C. exposure to an individual who has an infectious disease.
D. a physician administering a gamma globulin shot to a patient.
E. AandD.

Answer 4

A. transfer of bone marrow from one individual to another.

Question 5

IgG binding to neutrophils cells is mediated by:
A. Fc-dependent cellular homing mechanisms.
B. sensitization of Mast cells and basophils.
C. Fc receptors specific for IgG.
D. ICAM’s.
E. none of the above.

Answer 5

C. Fc receptors specific for IgG.

Antibodies of the IgG isotype coat (opsonize) microbes and promote their phagocytosis by binding to Fc receptors on phagocytes. Mononuclear phagocytes and neutrophils ingest microbes as a prelude to intracellular killing and degradation. These phagocytes express a variety of surface receptors that directly bind microbes and ingest them, even without antibodies, providing one mechanism of innate immunity. The efficiency of this process is markedly enhanced if the phagocyte can bind the particle with high affinity. Mononuclear phagocytes and neutrophils express receptors for the Fc portions of IgG antibodies that specifically bind antibody-coated particles. Microbes may also be coated by a product of complement activation called C3b and are phagocytosed by binding to a leukocyte receptor for C3b. The process of coating particles to promote phagocytosis is called opsonization, and substances that perform this function, including antibodies and complement proteins, are called opsonins.

Question 6

Avidity is important because:
A. it amplifies the binding strength of low affinity Fab’s.
B. Fc receptor binding depends on it.
C. G-protein-mediated signal transduction will not occur without it.
D. it result in the activation of high affinity antibody-producing clones.
E. none of the above.

Answer 6

A. it amplifies the binding strength of low affinity Fab’s.

Question 7

Mucosal immunity provides most of its protection by blocking
A. microbial receptors specific for colonization.
B. the complement cascade.
C. blocking penetration of undigested food products into the mucosal tissues.
D. A & C
E. none of the above

Answer 7

D. A & C

Question 8

Tissue macrophages are mature:
A. B cells
B. T cells
C. NK cells
D. Monocytes
E. none of the above.

Answer 8

D. Monocytes

Question 9

Which of the following is not a function of adjuvants?
A. forms an antigen depot.
B. provides non-specific T cell stimulation.
C. activates antigen-presenting cells.
D. activates the complement cascade.
E. none of the above.

Answer 9

D. activates the complement cascade.

Question 10

The lag phase of the secondary response is shorter than the primary response because:
A. the assays for detecting a primary response are not as sensitive.
B. the primary response requires considerable cell proliferation and differentiation to achieve a critical mass of cells to produce immunity.
C. of the lack of cytokines produced during the primary response.
D. none of the above.

Answer 10

B. the primary response requires considerable cell proliferation and differentiation to achieve a critical mass of cells to produce immunity.

Question 11

The lag phase of the booster response is:
A. very short, due to memory cells.
B. very short due to the lack of antigen presenting cells.
C. very short when dendritic cells are absent.
D. very short, due to the presence of accessory cells.

Answer 11

A. very short, due to memory cells.

Question 12

The location of complement activation is determined by:
A. the location of Fc receptors.
B. the location of dendritic cells.
C. the location of specific antibody/antigen complexes.
D. B & C.
E. none of the above.

Answer 12

C. the location of specific antibody/antigen complexes.

B is wrong because follicular DCs.

Question 13

Complement damage is generally limited to the immediate area in which complement is activated because of the:
A. short half-lives of the activated complement components and their rapid inactivation.
B. very low concentrations of the inactivated complement components in serum.
C. the inability to activate the system in the presence of IgG antibodies.
D. once activated, the destructive activities of complement are non-specific.
E. none of the above

Answer 13

A. short half-lives of the activated complement components and their rapid inactivation.

Question 14

Sensitization to foods is minimized by secretory IgA antibodies by:
A. The inflammatory response that occurs in the presence of food, these antibodies and complement.
B. Destroying the antigen presenting cells that would normally present the food antigens to T cells in the gut.
C. Blocking the penetration of intact food products into the gut.
D. All of the above

Answer 14

C. Blocking the penetration of intact food products into the gut.

Question 15

During serum sickness (a reaction to proteins in antiserum derived from a non-human animal source, occurring 4–10 days after exposure), kidney damage occurs as immune complexes form. Why?
A. The immune complexes are filtered by the kidneys and damage results from concomitant complement activation and neutrophil activity.
B. Antigen presenting cells rapidly bind all of the complexes in their MHC-encoded receptors.
C. Free antigen activates PAMP receptors in the kidneys which rapidly activate adaptive
immunity.
D. The immune complexes bind to Mast cells and are destroyed.
E. none of the above

Answer 15

A. The immune complexes are filtered by the kidneys and damage results from concomitant complement activation and neutrophil activity.

Question 16

Innate host defense mechanisms are critical to the protection of the body because:
A. they utilize pre-committed antigen presenting cells that have already been induced by other immune responses.
B. the antibodies derived from the innate response are critical to neutralize bacterial toxins.
C. they are highly specific for the invading pathogens that avoid PAMP receptor recognition.
D. they provide immediate, continuous protection in the absence of a specific immune response.
E. B & D

Answer 16

D. they provide immediate, continuous protection in the absence of a specific immune response.

Question 17

Which of the following complement regulatory proteins functions as a soluble protein that binds to C5b67 and prevents formation of the MAC on the membrane?
A. C1 INH
B. Factor H
C. S protein
D. Decay-accelerating factor (DAF)
E. Factor I

Answer 17

C. S protein

Fig. 13-16

Question 18

Which of the following complement regulatory proteins functions as a soluble protein that binds to alternative pathway C3 convertase and prevents formation of C5 convertase?
A. C1 INH
B. Factor D
C. S protein
D. Decay-accelerating factor (DAF)
E. Factor I

Answer 18

D. Decay-accelerating factor (DAF)

Question 19

Which of the following complement regulatory proteins functions as a soluble proactivator of C3 convertase?
A. C1 INH
B. Factor D
C. S protein
D. Decay-accelerating factor (DAF)
E. Factor I

Answer 19

B. Factor D

Fig. 13-7

Question 20

Which of the following complement regulatory proteins functions as a specific inhibitor of the classical pathway of complement activation?
A. C1 INH
B. Factor D
C. S protein
D. Decay-accelerating factor (DAF)
E. Factor I

Answer 20

A. C1 INH

Question 21

If knock out mice are prepared so that the complement protein Factor B is eliminated, what predictions would you make concerning the effect of the mutation on the steps of complement activation?
A. The C3 convertase for the classical pathway would not be able to form.
B. The C3 convertase for the alternative pathway would not be able to form.
C. The C3 convertase for the lectin pathway would not be able to form.
D. The C5 convertase for the classical pathway would not be able to form.
E. The C5 convertase for the lectin pathway would not be able to form.

Answer 21

B. The C3 convertase for the alternative pathway would not be able to form.

Question 22

Which of the following statements is true regarding the binding of a pentamer of IgM to antigen in terms of its ability to activate complement?
A. The planar form of IgM is the conformation obtained after a pentamer of IgM binds to multivalent antigen revealing binding sites for C1.
B. The staple form of IgM is the conformation obtained after a pentamer of IgM binds to multivalent antigen revealing binding sites for C1.
C. Individual IgM pentamers are unable to activate complement unless since there is a requirement for 2 or more IgM pentamers bound.
D. IgM pentamers do not activate complement; complement activation is mediated only by IgG.
E. none of the above statements are correct.

Answer 22

B. The staple form of IgM is the conformation obtained after a pentamer of IgM binds to multivalent antigen revealing binding sites for C1.

Question 23

The alternative pathway of complement activation is characterized by the functions listed below, except
A. activation of complement components beyond C3 in the cascade.
B. participation of properdin.
C. generation of anaphylatoxins.
D. use of C4
E. all of the above answers are correct for the alternative pathway.

Answer 23

D. use of C4

Question 24

The cytotoxic T cells mediates killing of target cells by which of the following?
A. The CTL produces perforin which functions to form protein pore structures in the membrane of the target cell.
B. The CTL produces granzymes which functions to form protein pore structures in the membrane.
C. The CTL produces granzymes which enter through perforins and functions to initiate apoptosis of the target cell.
D. CTL contain the FAS Ligand which binds to the FAS receptor on target cells and triggers apoptosis.
E. Answers A, C, and D are correct.
F. Answers B and D are correct.

Answer 24

E. Answers A, C, and D are correct.

Question 25

NK cells are activated by several cytokines that are produced by specific cell types including which of the following?
A. IL-12 which is produced by macrophages.
B. IL-12 which is produced by virally infected cells.
C. IFN-gamma and IFN-beta which are produced by virally infected cells.
D. Answers A and C are correct.
E. Answers B and C are correct.

Answer 25

A. IL-12 which is produced by macrophages.

Question 26

Which of the following statements about cytokines synthesized by CD4+ TH1 cells and TH2 cells is incorrect?
A. Cytokines produced by TH1 cells include IFN-γ and TNF-β.
B. Cytokines produced by TH2 cells are important in allergic responses.
C. TH1 cells secrete cytokines that induce macrophages.
D. TH2 cells secrete cytokines that activate CD8+ T cells.
E. TH2 cells secrete cytokines that may inhibit TH1 cells formation.

Answer 26

D. TH2 cells secrete cytokines that activate CD8+ T cells.