Big Picture Immunity to Infection

Question 1

Innate immune responses are important in the initiation of adaptive responses because
a. antigen cannot bind B cells until it has first bound complement.
b. inflammatory chemokines attract naïve B and T cells to the infection site to be activated.
c. inflammatory cytokines and acute phase proteins stimulate the expression of co-stimulatory molecules on dendritic cells.
d. lymphocytes cannot enter the secondary lymphoid organs until inflammatory cytokines upregulate CAM expression on HEV.
e. T cells are stimulated to express co-stimulatory molecules by acute phase proteins.

Answer 1

c. inflammatory cytokines and acute phase proteins stimulate the expression of co-stimulatory molecules on dendritic cells.

Question 2

Th0 differentiation into Th1 or Th2 cells is influences by all of the following EXCEPT
a. antigen density on the APC MHC.
b. avidity of peptide binding to TCR.
c. cytokines being produced by nearby dendritic cells.
d. cytokines being secreted by nearby T cells.
e. whether the T0 cell has already begun to make IL-2.

Answer 2

e. whether the T0 cell has already begun to make IL-2.

Question 3

Armed effector CTL find and kill their target cells in
a. draining lymph nodes.
b. the site of pathogen entry into the body.
c. the spleen.
d. whatever tissues have APC to provide co-stimulatory signals.
e. whatever tissues are infected.

Answer 3

e. whatever tissues are infected.

Question 4

Naïve lymphocytes enter the lymph nodes
a. any time they pass by the lymph node HEV.
b. any time inflammatory chemokines signal them to go to the lymph nodes.
c. only during infection.
d. only when their specific antigen is NOT present in the tissues.
e. only when their specific antigen is present.

Answer 4

a. any time they pass by the lymph node HEV.

Question 5

Effector B cells (plasma cells) secrete antibody in the
a. bone marrow.
b. germinal centers.
c. primary follicles.
d. secondary follicles.
e. T cell follicles.

Answer 5

a. bone marrow.

Question 6

Immune memory is provided by persisting
a. antibody molecules.
b. effector CTL.
c. memory cells that can be activated by antigen to become effectors.
d. plasma cells
e. All of the above contribute to immune memory.

Answer 6

c. memory cells that can be activated by antigen to become effectors.

Question 7

Lymphocytes which are part of the MALT do not generally recirculate through the peripheral lymph nodes because
a. MALT lymphocytes do not recirculate.
b. the antigens for which they are specific cannot go to the lymph nodes.
c. the APC that activate them are found only in the MALT.
d. they are negatively selected against MALT self antigens in the bone marrow and must stay in the MALT to avoid inducing autoimmunity
e. they bind better to MAdCAM on the mucosal vascular endothelium than they do to CD34 on the lymph node HEV.

Answer 7

e. they bind better to MAdCAM on the mucosal vascular endothelium than they do to CD34 on the lymph node HEV.

Question 8

All of the following are part of the gut-associated lymphoid tissue EXCEPT the
a. adenoids.
b. appendix.
c. enterocytes.
d. M cells.
e. Peyer’s Patches.

Answer 8

c. enterocytes.

Question 9

The function of the M cells is to
a. induce apoptosis in food antigens.
b. kill infected enterocytes.
c. migrate to the Peyer’s Patches and present antigen to T cells.
d. phagocytose or endocytose antigen.
e. secrete neutralizing IgA.

Answer 9

d. phagocytose or endocytose antigen.

Question 10

The mucosal equivalent of the lymph node, where naïve T and B cells are activated, is the
a. appendix.
b. crypt.
c. MAdCAM-1 vesicle.
d. Peyer’s Patches.
e. submucosal lymphoid tissue.

Answer 10

e. submucosal lymphoid tissue.

Question 11

Plasma cells activated in the gut-associated lymphoid tissue secrete IgA in the
a. bone marrow.
b. lamina propria lymphoid tissues.
c. mucosa of gut, lungs, and genital tracts.
d. Peyer’s Patches.
e. spleen

Answer 11

b. lamina propria lymphoid tissues.

Question 12

Specialized gd T cells in the mucosal epithelium
a. are educated in the thymus to be tolerant to food antigens.
b. become ab T cells when stimulated by Th1 cytokines.
c. kill infected enterocytes expressing MIC-1 and MIC-2.
d. recognize peptides presented on Class I MHC.
e. remove food antigens before they can be phagocytosed by M cells.

Answer 12

c. kill infected enterocytes expressing MIC-1 and MIC-2.

Question 13

The principal effector function that eliminates intestinal pathogens is
a. CTL in the Peyer’s Patches.
b. macrophages in the intestinal lumen.
c. neutralizing secretory IgA in the mucus.
d. opsonizing secretory IgA on M cells.
e. tolerance.

Answer 13

c. neutralizing secretory IgA in the mucus.

Question 14

Normal flora in the intestine
a. are neither harmful nor beneficial.
b. block adherence of pathogens by secreting toxins that kill them.
c. cannot cause disease.
d. induce no immune response unless they damage the intestinal epithelium.
e. None of the above is true.

Answer 14

e. None of the above is true.

Question 15

Intestinal pathogens
a. cannot survive in the stomach because of the low pH there.
b. mimic food antigens to avoid the immune response.
c. must enter the body to cause disease.
d. stimulate inflammatory cytokine secretion to suppress immune responses.
e. use M cells as an entry way into the body.

Answer 15

e. use M cells as an entry way into the body.

Question 16

Food antigens induce tolerance by
a. activating regulatory cells that suppress immune responses.
b. entering the body through enterocytes instead of M cells.
c. failing to induce inflammatory cytokine production.
d. inducing clonal proliferation in specific T cells.
e. Both a and c are correct.

Answer 16

e. Both a and c are correct.

Question 17

A secondary humoral response
a. becomes detectable in serum overnight following antigen stimulation.
b. is T cell independent.
c. produces antibody of lower average affinity than a primary response
d. requires the presence of antibody from the primary response to initiate activation of memory cells.
e. results in high serum levels of IgG.

Answer 17

e. results in high serum levels of IgG.

Question 18

Primary and secondary humoral immune responses do NOT differ in their
a. antibody affinities.
b. effector mechanisms.
c. kinetics.
d. peak antibody titers
e. ratio of IgM:IgG.

Answer 18

b. effector mechanisms.

Question 19

An Elvis impersonator comes to you with a sore throat. You run some tests and learn that his C3 levels are low, IgM levels are moderate, and IgG levels are very high. This laboratory data tells you that your patient
a. does not have an infection, because complement levels rise during an infection.
b. has not previously been exposed to the infectious organism.
c. is probably undergoing a secondary immune response.
d. must have a bacterial infection, since viruses cannot induce an IgG response.
e. must be the King himself.

Answer 19

c. is probably undergoing a secondary immune response.

Question 20

Original antigenic sin
a. activates memory cells more quickly than naïve cells.
b. indicates that memory responses suppress the activation of naïve cells.
c. occurs in response to eating apples.
d. occurs when an autoimmune response is produced.
e. only occurs during responses to influenza virus.

Answer 20

b. indicates that memory responses suppress the activation of naïve cells.