011615 microbiota

Question 1

mucins’ role in host defense

Answer 1

binds some commensals
bacterial exclusion
containment of secreted antibodies and antimicrobials

Question 2

paneth cell AMPs-give ex

Answer 2

defensins
lysozyme
phospholipase A2
RegIIIgamma

Question 3

predominant immunoglobulin secreted as a defense in the mucosal areas

Answer 3

IgA

Question 4

how is mucosal IgA inducted?

Answer 4

1st way: bacteria is engulfed by dendritic cell. DC goes to mesenteric lymph node to induce B cell activation. get plasma cell secretion of IgAs

2nd way: M cell encounters bacteria. then activatres B cells in Peyer’s patches

Question 5

activities of IgA

Answer 5

surrounds microbe and repels attachment to mucosal surface

mucus trapping-may associate with mucins and trap microbes in mucus blanket

virus neutralization

etc

Question 6

if you lack a good immune system, what happens?

Answer 6

commensal microbiota can invade

Question 7

healthy microbiota contains what

Answer 7

balancec omposition of three major classes of bacteria:

symbionts, commensals, pathobionts (live as commensals but have potential to induce pathology)

Question 8

microbial composition is determined by

Answer 8

site in GI
O2 tension
innate immune factors
host nutrition/diet

Question 9

role of intestinal microbiome

Answer 9

protective against pathogens
induce immune system development
metabolic fxns

Question 10

fxn of short chain fatty acids

Answer 10

commensal bacteria ferment nondigestable dietary polysaccharides to produce short chain fatty acids

SCFAs regulate PMNs, DCs, macrophages, epithelial cells. SCFAs regulate expression of virulence factors on bacterial pathogens so that they are not so toxic

Question 11

abnormalities in composition of microbiome can result in increased risk of autoimmune, allergic, infectious and metabolic diseases: true or false

Answer 11

true