16 Mucosal Immunity Flashcards Preview

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Flashcards in 16 Mucosal Immunity Deck (39):
1

Is mucosal immunity a sterile environment?

No dirty environment. Systemic immunity is sterile

2

Systems of mucosal immunity?

gut, airway, urogenital tract

3

Where are 75% of the immune systems cells located?

mucosal immunity

4

do microbes outnumber host cells?

10:1 yes

5

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

True

6

Are immune responses down regulated in mucosal immunity?

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

7

Why is mucous secreted by gut and respiratory cells?

keep bacteria moving to prevent adherence

8

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

defensins

9

What are alpha defensin made by?

PMN/NK

10

Where are alpha defensins found in?

Paneth cells of gut and female urogenital tract

11

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

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

12

What do histatins do?

fight infections in the oral cavity

13

are cathelicidins active with gram + and - bacteria?

yes

14

What cells pass microbes over to APCs in the follicles?

Mcells

15

T or F --M cells lack glycocalyx on cell surface

true- allow them to endocytose Ag

16

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

basolateral

17

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

true---lymphocytes and DCs snuggle

18

What cells proliferate from M cell activation?

particularly B cells so they can exert effector functions downstream

19

Are overactive immune responses in the gut desirable?

No--too much Ag…it would devastate the tissue

20

What suppressive functions are there in the gut immune regulation?

Tregs
Cytokines IL 10

21

What are CD8 cytotoxic T lymphocytes interspersed between epithelial cells?

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

22

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

CD8aa homodimers

23

Can IEL possess FasL, perforin and cytolytic granules?

Yes--activated or memory phenotype for quick response

24

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

Tregs

25

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

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

26

Where is 90% of IgA in the body secreted?

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

27

Path of Mucosal B cell response?

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

28

What crosses epithelial barriers in dimeric fashion via pIgR?

IgA

29

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

IgA

30

What are the properties of IgA?

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

31

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

PIgR

32

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

True

33

what allows for formation of IgA dimer?

J chain

34

Where do CD4 T cells traffic to in the gut?

mesenteric Lymph nodes

35

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

True

36

What provide passive immunity to neonates?

IgA

37

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

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

38

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

Crohn's and ulcerative colitis

39

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

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