Deck 10: Preventing Infection at Mucosal Surfaces

Question 1

_____ microorganisms are microbes that colonize mucosal surfaces but under normal circumstances do not cause disease.

A)Opportunistic
B)Commensal
C)Parasitic
D)Mesenteric
E)Pathogenic.

Answer 1

B

Question 2

Explain how secondary lymphoid tissues of the mucosa are (A)similar to and (B)different from secondary lymphoid tissues elsewhere in the body (the systemic immune system).

Answer 2

A.Mucosal secondary lymphoid tissues have the same general microanatomy and organization as those of secondary lymphoid tissues found at other anatomical locations,with distinct compartmentalization of B-cell and T-cell zones.Both mucosal and systemic secondary lymphoid tissues function as sites where naive lymphocytes are activated by antigen and adaptive immune responses are initiated. B.In the systemic immune system,adaptive immune responses are activated in secondary lymphoid tissues that are quite distinct from and often distant from the site of infection.In contrast,in the mucosal immune system,the adaptive immune response is initiated at secondary lymphoid tissues at the site of infection.

Question 3

Waldeyer's ring includes which of the following? (Select all that apply.)

A)Peyer's patches
B)lingual tonsils
C)adenoids
D)mesenteric lymph nodes
E)palatine tonsils.

Answer 3

B,C,E

Question 4

Laboratory animals reared in gnotobiotic conditions _____.

A)are fed probiotics to disrupt the composition of their microflora
B)lack normal gut microbiota
C)develop appendicitis
D)have larger secondary lymphoid tissues than do control animals
E)have elevated levels of SIgA in the gut lumen.

Question 5

Identify ways in which intestinal macrophages are (A)similar to and (B)different from macrophages in non-mucosal tissues.

Question 6

Which of the following migrates from non-mucosal tissue to draining lymph nodes to facilitate the induction of adaptive immune responses?

A)dendritic cells
B)macrophages
C)NK cells
D)neutrophils
E)commensal microorganisms.

Question 7

of the following are part of Waldeyer's ring except _____.

A)appendix
B)palatine tonsils
C)lingual tonsils
D)adenoids.

Question 8

which anatomical location are Peyer's patches?

A)stomach
B)small intestine
C)cecum
D)large intestine
E)Waldeyer's ring.

Question 9

Describe the route that a Peyer's patch-activated T lymphocyte follows,beginning with a naive T lymphocyte in a high endothelial venule and ending with an effector T lymphocyte in the lamina propria.

Question 10

_____ assists in the differentiation of blood-derived monocytes into intestinal macrophages.

A)TGF-β
B)B7
C)IL-12
D)CXCL8
E)CD14.

Question 11

_____ makes up the membranes of connective tissue that help to anchor the gastrointestinal tract and hold it in place.

A)The mesentery
B)Peyer's patches
C)The lamina propria
D)The subepithelial dome
E)Waldeyer's ring.

Question 12

Mucosae of a healthy intestinal tract _____.(Select all that apply.)

A)have a large number of activated T and B cells
B)harbor T cells bearing a very wide diversity of antigen specificities
C)contain intraepithelial lymphocytes
D)have large numbers of resident neutrophils
E)are populated with both α:β and γ:δ effector T cells.

Question 13

Describe two ways in which dendritic cells capture antigen from the intestine for presentation to T lymphocytes.

Question 14

large population of microbes that contribute to the gut microbiota and have an important role in food processing are called _____.

A)lamina propria
B)Peyer's patches
C)microfold cells
D)commensal microorganisms
E)opportunists.

Question 15

Which of the following describe M cells in the gut? (Select all that apply.)

A)They derive their name from mucus cells.
B)They are located in the dome of a Peyer's patch.
C)They deliver antigens and pathogens from the lymphoid tissue to the luminal side of the gut mucosa by transcytosis.
D)They are protected from digestive enzymes by a thick glycocalyx and a layer of mucus.
E)They do not directly participate in antigen processing or presentation.

Question 16

Because the mucosae _____,this tissue is predisposed to infection.

A)constitute thin,permeable barriers
B)secrete a continuous layer of mucus
C)generate enzymes and proteoglycans
D)are associated with secretory IgA production
E)are not connected to the lymphatics.

Question 17

All of the following are expressed by intestinal epithelial cells except _____.

A)NOD receptors
B)FcαR
C)TLRs
D)MHC class II
E)NFκB.

Question 18

Unlike secreted mucins,membrane mucins _____.

A)do not trap and kill nearby microorganisms
B)are not cross-linked by disulfide bonds
C)do not possess repetitive domains
D)are not glycosylated
E)are encoded by only one gene in humans.

Question 19

Identify three locations where secretory IgA can bind to antigens in mucosal tissue,and for each give the fate of the antigen upon binding to secretory IgA.

Question 20

In addition to M cells,_____ can capture pathogens directly from the lumen of the gut.

A)intraepithelial lymphocytes
B)plasma cells
C)Paneth cells
D)dendritic cells
E)macrophages.

Question 21

Secretory IgA binds to pathogens in all of the following locations except the _____.

A)endosomes of an M cell
B)lamina propria
C)lumen of the gut
D)blood
E)Peyer's patches.

Question 22

Describe four actions of effector CD4 T_H2 cells that provide protection from infections by intestinal helminths and lead to expulsion of the parasites from the gastrointestinal tract.

Question 23

_____ compensates for the absence of secretory IgA in selective IgA deficiency because it can be secreted by mucosal tissues using the same receptor needed for transcytosis.

A)Monomeric IgA
B)IgD
C)IgE
D)IgG
E)IgM.

Question 24

Which of the following is not an activity associated with secretory IgA and secretory IgM in mucosal secretions?

A)toxin neutralization
B)complement fixation
C)binds to mucin through disulfide bonds
D)restricts commensal microorganisms to gut lumen
E)limits population size of commensal microorganisms.

Question 25

In which of the following tissues is IgA2 produced at approximately twice the level of IgA1?

A)spleen
B)mammary glands
C)large intestine
D)gastric mucosa
E)upper small intestine.

Question 26

What is the function of the TNF-family cytokine APRIL made by epithelial cells of the colon?

A)elevates rate of M-cell proliferation
B)degrades IgA1
C)mediates isotype switching from IgM to IgA2
D)binds to J chain of dimeric IgA
E)upregulates MAdCAM-1 production.

Question 27

The cytokine influencing eosinophil development and function during helminth infections is _____.

A)IL-3
B)IL-9
C)IL-19
D)IL-10
E)IL-5.

Question 28

_____ is the vascular addressin found on endothelial cells of intestinal mucosa that binds to integrins of gut-homing effector lymphocytes.

A)CCL25
B)C-cadherin
C)NOD1
D)MAdCAM-1
E)CCR9.

Question 29

Intracytoplasmic bacteria in enterocytes of the gastrointestinal tract are detected by _____.

A)poly-Ig receptor
B)major basic protein
C)MIC-A and MIC-B
D)NOD proteins
E)receptors for phosphoantigens.

Question 30

What property of the mucosal immune system enables breast milk to contain antibodies against microorganisms encountered in the gut or other mucosal tissues? Explain your answer.

Question 31

Explain why individuals who have the condition selective IgA deficiency do not succumb to repeated infection through mucosal surfaces.

Question 32

M cells,unlike dendritic cells,_____.

A)do not secrete digestive enzymes into the lumen of the gut
B)are not associated with Peyer's patches
C)do not facilitate the transport of microbes from the gut lumen to the GALT
D)do not process and present their antigen to naive T cells.

Question 33

Why do children who have had their tonsils or adenoids removed respond less effectively to the oral polio vaccine than children who still have these tissues?

Question 34

IgA proteases produced by Streptococcus pneumoniae mediate all of the following effects except _____.

A)separation of Fab and Fc regions
B)interference with FcαR-mediated endocytosis
C)enhanced adherence of Fab-coated bacteria to mucosal epithelium
D)preferential cleavage of IgA2 over IgA1.

Question 35

The significance of MAdCAM-1 on the endothelium of blood vessels is that it binds to _____.

A)the integrin α₄β₇ on effector lymphocytes homing to mucosal tissues
B)B cells destined to become intraepithelial lymphocytes
C)dendritic cells,and causes the upregulation of antigen processing and presentation
D)the chemokine CCL25,which is secreted by gut epithelia
E)intestinal helminths,and mediates killing of these parasites.

Question 36

If a B cell has been activated by antigen in the mucosa of the respiratory tract,then _____.(Select all that apply.)

A)lactating mothers will provide antigen-specific natural IgA in breast milk
B)secretory IgA will be synthesized in the lamina propria of all mucosae
C)it does not enter the bloodstream but instead remains in the mucosa and differentiates into an effector B cell
D)it will recirculate through all mucosal tissues,including respiratory and gastrointestinal mucosae
E)monomeric IgA is secreted into the lamina propria.

Question 37

The dominant immunoglobulin synthesized at mucosal surfaces is _____.

A)IgA
B)IgD
C)IgE
D)IgG
E)IgM.

Question 38

Secretory IgA is best described as _____.

A)a non-inflammatory immunoglobulin that restricts the passage of antigens across mucosal surfaces
B)a complement-activating immunoglobulin that causes destruction of invasive microflora through the membrane-attack complex
C)an opsonizing antibody that facilitates uptake by M cells through Fc receptors
D)an inflammatory immunoglobulin that stimulates the chemotaxis of neutrophils into mucosal surfaces
E)a monomeric IgA that neutralizes antigen effectively at mucosal surfaces.

Question 39

Secretory IgA and _____ can bind to the poly-Ig receptor and be transported into the lumen of the gut or across other mucosal surfaces.

A)IgG
B)IgE
C)IgD
D)monomeric IgM
E)pentameric IgM.