10 Oral Tolerance Flashcards
mucosal immunity, in addition to providing defense at all mucosal surfaces does what
prevents Ag from entering circulation
prevents systemic immune response to an inappropriate Ag exposure
low dose of an oral Ag will result in
induciton of Th2 (IL-4 and -10) and TGFbeta secreting regulatory cells
leads to active suppression and immunologic hyporesponsiveness
high dose of an oral Ag will result in
deletion of anergy of Th1 and Th2 cells –> clonal anergy/depletion and
immunological hyporesponsiveness
stratification vs compartmentalization
stratification: minimizing contact between bacteria and epithelial layer by mucins, defensins, IgA
Compartmentalization: confining bacteria to intestinal sties and limiting exposure
describe immune exclusion
IgA traps Ag at mucosal surface where it is subject to degradation by defensins
intestinal epithelial cells play what important roleS in mucosal immunity
constant translocation of IgA (or IgM because J chain)
nonprofessional Ag presentation
in order to limit inflammation in GI tract, what receptor is moved and to where
TLRs are located on the basolateral side as opposed to apical side (only what gets past barrier induces inflammation)
NLRs (for intracellular stuff) remain
regardless of IgAs presence in the lamina propria of GI, what is produced and why
Secretory component that transports Ab across mucosal epithelial cell layer
ensures SC is not limited during an immune response
sits above peyer’s patches, uptakes whole Ag and transports it into lumen for DC sampling
Microfold cells (M)
CD103+ cells
Specialized DCs in the GALT
can extend dendrites into lumen
produce Retinoic acid
produce anti-inflammatory cytokines: TGF-beta, IL-10 and IL-2
B cells in peyers patches primarily produce
IgA
IgA is important in maintaining homeostasis because
it does not fix complement, only neutralizes through binding - therefore clears immune complex without inflammation
gamma delta T cells are unique in what two ways
recognize lipid Ag (not just protein like their alpha:beta counterparts)
can be directly activated by DAMPs and PAMPs
why are most IgA deficiencies not diagnosed
IgM will still be secreted through epithelial layer in absence of IgA due to SC
IBD is caused by what deficiencies of the immune system
defective defensin - inadequate negative regulation
overactive Th17
granulamatous inflammation by Th1
defective Treg function
malnutrition is to immunosuppression/susceptibility to infection as overnutrition is to
immunoactivation - susceptibility to inflammatory disease
