Mucosal Immunity Flashcards
lamina propria
germ free - few LP
infectious environment - many LP
paneth cells
defensins -antimicrobial peptides
peyers patches
non-encapsulated but like lymph node
T and B cell population and APCs
M cells
no microvilli
-antigen presentation to peyers patches
antibody of gut
IgA
innate immunity
goblet cells
epithelial cells
paneth cells
M cells
mucins
O-linked oligosaccharides
-secreted and membrane bound (glycocalyx)
NLR
in cytoplasm of epithelium cells
TLR
on basolateral surface
also on dendritc cells of lamina propria (low levels)
defensins
small cationic peptides
three disulfide bonds
small bowel -alpha (HD5 HD6)
-by neutrophils
colon -beta
-by epithelial cells
adaptive immunity
IgA
Th17
suppression
peyers patches
part of GALT
follicle - B cells rich (IgM and IgD)
dome region - T, B, DC, macrophages
M cells
top of domes flat epithelial cells MHC class II
antigen capture
dendritic cell extends arm to lumen
dendritic cell sampling
IL-6 and TGF-B
T cells - IFN gamma and IL 17
FoxP3 T reg cells
dampen the immune response
regulatory dendritic cells
DC103
alpha4beta7
binds MadCAM
for homing of lymphocytes
CCR10
CCL28 homing to colon and breast tissue
CCR9
homing to small intestine epithelium
RALDH
synthesis of retinoic acid from Vit A
IgA
neutralizes bio active antigens
-secreted into gut lumen
prevents antigen uptake
inhibit adherence of bacteria to epithelial surface
serum IgA
low levels
does not induce inflammation (fix complement)
Kupffer cells
filter out IgA complexes with antigen bound
T cell independent IgA class switch
APRIL, BAFF, TGF-beta to B cell
poly-Ig receptor
transport IgA and IgM unidirectionally to lumen
lamina propria cells
mostly CD4 T cells
Th17
Th2
Th2
against parasites
IL-4 and IL 13
Th17
colonization and protection of gut
IL-17 and IL-22
FoxP3
on T reg cells
deficiency - IBS
IBD
crohns - entire thickness (terminal ileum)
ulcerative colitis - colonic mucosa
celiac disease
gluten sensitivity
tumors
can occur in prolonged immune responses
crohns disease
perianal fistulas
overactive Th17
can contribute to chronic inflammation
Reg-III-gamma
antibacterial lectin
celiac disease
autoantibodies - anti-gliadin, transglutaminase, endomysium
histology - villous atrophy
mediate by T cells
food allergy
type I hypersensitivity
IgE mediated
non-IgE - Th2 mediated
need prior exposure
treatment - epi-pen, benadryl, IV corticosteroids
