#12 Gut Immunity, Nutrition, and Adverse Food Reactions

Question 1

Where does T cell activation occur in the gut?

Answer 1

MLNs (mesenteric lymph nodes)

*Under epithelial and just under the villi, connected by lymphatics

Question 2

What is immune exclusion?

Answer 2

Limiting pathogens via IgA (inhibit bacteria from binding to epithelium)

(secretory IgA=sIgA)

Question 3

Gut lamina has a lot of what?

Answer 3

IgA and IgM plasma cells

Question 4

What do T reg cells do?

Answer 4

Suppress Th1, Th2, Th 17

Question 5

What does Th-17 do?

Answer 5

Pro-inflam: IL-17, IL-22

Accumulate in intestine (antibiotics decrease their #)

SFB: proliferate Th-17 grow

Question 6

What do microflora flagellin do?

Answer 6

• Make GALT
• Digestion of carbs, conjugation of bile, make vitamins

Help make retinoic acid → differentiation → IgA (regulate gut microflora)

Question 7

SFB vs PSA

Answer 7

SFB: ↑Th-17 → ↑inflammation

PSA: from Bacteroides fragilis: ↑ T reg cells

Question 8

Lack of microflora leads to…

Answer 8

Lack of microflora → salmonella flagelin binds TLR5 → act. IKB → translocation of NFkb → ↑ inflammation (pro-inflam. genes)

*Presence of microflora takes NFkB out of nucleus via PPAR

Question 9

A combination of genetic factors and environmental factors result in disruption of the microflora, a process termed

Answer 9

Dysbiosis