16 Mucosal Immunity

Question 1

Is mucosal immunity a sterile environment?

Answer 1

No dirty environment. Systemic immunity is sterile

Question 2

Systems of mucosal immunity?

Answer 2

gut, airway, urogenital tract

Question 3

Where are 75% of the immune systems cells located?

Answer 3

mucosal immunity

Question 4

do microbes outnumber host cells?

Answer 4

10:1 yes

Question 5

T or F —activated/memory T cells predominate in the absence of infection in mucosal immunity?

Answer 5

True

Question 6

Are immune responses down regulated in mucosal immunity?

Answer 6

yes—there are also inhibitory macrophages and tolerance-inducing DCs

Question 7

Why is mucous secreted by gut and respiratory cells?

Answer 7

keep bacteria moving to prevent adherence

Question 8

what are antimicrobial peptides that insert into and lyse microbial membranes?

Answer 8

defensins

Question 9

What are alpha defensin made by?

Answer 9

PMN/NK

Question 10

Where are alpha defensins found in?

Answer 10

Paneth cells of gut and female urogenital tract

Question 11

What are beta-defensins expressed by? where are they located?

Answer 11

epithelial cells and are found in airway, gut, mammary glands, and pancreas

Question 12

What do histatins do?

Answer 12

fight infections in the oral cavity

Question 13

are cathelicidins active with gram + and - bacteria?

Answer 13

yes

Question 14

What cells pass microbes over to APCs in the follicles?

Answer 14

Mcells

Question 15

T or F –M cells lack glycocalyx on cell surface

Answer 15

true- allow them to endocytose Ag

Question 16

On what surface of the intestine are M cells associated with lymphocytes?

Answer 16

basolateral

Question 17

t or F–basolateral side of m cells are pocketed?

Answer 17

true—lymphocytes and DCs snuggle

Question 18

What cells proliferate from M cell activation?

Answer 18

particularly B cells so they can exert effector functions downstream

Question 19

Are overactive immune responses in the gut desirable?

Answer 19

No–too much Ag…it would devastate the tissue

Question 20

What suppressive functions are there in the gut immune regulation?

Answer 20

Tregs

Cytokines IL 10

Question 21

What are CD8 cytotoxic T lymphocytes interspersed between epithelial cells?

Answer 21

IELs composed of both CD8 alphabeta and gamma/delta. Regulatory and cytolytic functions.

Question 22

What is binds to thymus leukemia antigen expressed by mucosal cells and preventing proliferation of IEL?

Answer 22

CD8aa homodimers

Question 23

Can IEL possess FasL, perforin and cytolytic granules?

Answer 23

Yes–activated or memory phenotype for quick response

Question 24

What acts as a sink for IL-2 and secretes suppressive cytokines like IL-10?

Answer 24

Tregs

Question 25

Trafficking of lymphocytes that were induced in the MALT don't use CD62L (L selection). Wht do they use?

Answer 25

a4B7 integrin to bind to mucosal addressin cell adhesion molecule [MadCAM-1]

Question 26

Where is 90% of IgA in the body secreted?

Answer 26

b cells in the mucosal sites--IgA is made 2:1 over IdG in the body although IgG is more dominant in the serum

Question 27

Path of Mucosal B cell response?

Answer 27

prime in MALT by T cells---->proliferate---->home to distal mucosa of effector sites---->receive more signals to differentiate into plasma cells---->secret IgA

Question 28

What crosses epithelial barriers in dimeric fashion via pIgR?

Answer 28

IgA

Question 29

What neutralizes and binds up bacteria and other microbes so they can't enter the body and harm the host?

Answer 29

IgA

Question 30

What are the properties of IgA?

Answer 30

inhibit bacterial adhesion inhibits macromolecule absorption inhibit inflammatory effect of other isotypes neutralize virus, bacteria, toxins

Question 31

what allows IgA to bind mucus keeping it in the gut?

Answer 31

PIgR

Question 32

T or F- PigR can also bind to certain bacterial proteins such as E coli?

Answer 32

True

Question 33

what allows for formation of IgA dimer?

Answer 33

J chain

Question 34

Where do CD4 T cells traffic to in the gut?

Answer 34

mesenteric Lymph nodes

Question 35

T or F--In mesenteric lymph nodes, CD4 T cells can induce class switching of B cells from IgM to IgA?

Answer 35

True

Question 36

What provide passive immunity to neonates?

Answer 36

IgA

Question 37

Gluten sensitivity, wheat allergy, and celiac disease is a result of what?

Answer 37

uncontrolled T cell activation---->inflammation and loss of villi in mucosa brought on by loss of tolerance to food antigens

Question 38

Inappropriate inflammatory reactions to commensal microbials in the gut are associated with what 2 diseases?

Answer 38

Crohn's and ulcerative colitis

Question 39

Which cells activate the IEL cells in the gut? How do they activate(receptors)?

Answer 39

Intestinal cells are the activators through on classical MHC. TCR binds to CD1D CD8 binds to gp180