Mucosal Immunity Flashcards
largets deposit of lymphos?
mucosa
do B cells get to epithelium?
yes
MALT
largest lymph tiss.
60-70% of all lymphos
has subdivisions
PP
peyers patch
sample antigens through M-cells
ILF
clusters of lymphocytes located throughout the length of small intestine
omstly B cells
act as inductive sites for Mucosal immune responses
CPs
cryptopatches
could be a site of intraepithelial T lymph development.
may be precursors to ILFs
IEC, Enterocyte
AKA absorptive epi cells
most intestinal epithelia is made up of these cells, covered in mucus and glyccalix
goblet cell
secretes mucins: heavily glycosylated proteins. 2 types.
surface and secreted.
paneth cells
make antimicrobial peptides: a-defensins, cause cell wall rupture.
M cell
microfold cell, specialized epi cell.
no villi, folded BM, dont secrete mucus or enzymes, lack a surface glycocalix.
expose themselves to gut environment, take up antigen.
pathogenic exploitation of Mcells
salmonella kills them. polio and retros are taken in through transcytosis as well
how many IEL per epithelial cells
1 for every ten
IEL traits
limited TCR diversity.
have specific receptor for binding E-cadherin
mostly CD8, activated phenotype. (primed)
IgA
can be transported through the lumen both ways.
what are the 4 ways antigen gets presented to Tcells?
.
what are the two APs in the gut?
Effector- CX3CR1+, stimulate protective effector Tcell responses
Regulatory- CD103+, stimulate regulatory Tcell responses. immunity suppression.
retinoic acid
secreted by DCs to activate regulatory T cells.
naive t cells receive it and go through foxP3
polarization of TLRs
this helps keep regulation and effect in balance.
can be on baso and luminal sides.
ex. TLR 9 on both sides, in the lumen it inhibits NFkB, on the baso side it activates it.
how does a mucosa activated lympho find its way back to the gut?
integrins and chemokines!
they mediate the trafficking.
IgA defficiency
compensated by IgM, but still more susceptible.
think about tolerance vs immunity.
think about anatomical specialized functions
think about special IgA
.
