Mucosal Immunity 2 Flashcards
What is the main site for oral tolerance induction?
Mesenteric lymph nodes
Oral tolerance?
Avoidance of an immune response to food
Inferior rectal nodes drain into?
Inguinal nodes
What is route of B cells and T cells into mesenteric lymph nodes?
They will be arriving via high endothelial venules from peyers pathches via MLN to thoracic duct
Damage to liver can cause?
Leakage of LPS causing low grade fever, bypass through splenic vein
Intraepithelial lymphocytes are located?
In basolateral portion of the epithelium
What are features of intraepithelial lymphocytes?
Irregular shape, long extensions in close contact with neighbouring epithelial cells.
Mixed with eosinophils which can make up to 12% in intraepithelial cell preparations
Tissue resident memory T cells?
TCR alpha beta CD8 alpha beta
TCR alpha beta CD8 alpha alpha
TCR alpha beta CD4
What binds to stress receptors on the damaged gut epithelial cells MIC-A MIC-B?
NKG2D- Tcells that carry NK cell receptors
CD8 alpha alpha
And kill by apoptosis
What do intraepithelial CD8 T cells produce?
IFN gamma and are important in killing infected epithelial cells
Bacteria in the gut lumen induce?
IL-17 producing T helper cells
What do IL 17 and 22 do?
Interact with receptors on epithelial cells to regulate production of mucins or defensins.
Classic Th17 cells produce?
Il 17 and IFN gamma and are cytotoxic, may kill endothelial cells
T regs are produced in response to?
Presence of retinoids acid and TGF B, produced by dendritic cells
Treg’s produce?
Il 10, helpful in tolerance
Immune exclusion?
Immune system labels antigens so they don’t cause an immune response, done by IgA
IgA is?
Dimeric coupled by J chain
What enables trans-endothelial transport of dimeric IgA and igM?
Poly-ig receptor
Why do TLRs on basolateral surface not trigger inflammation?
Better to tighten junctions than cause inflammation
Homing?
T cells and B cells have to return to the effector sites adjoining the induction sites where they are primed.
Homing happens through?
Imprinted on cells by regulation of the gut associated lymphoid tissues, receptors on venules
Adhesion molecules on lymphocytes and receptor molecules on endothelial cells
Dendritic cells are induced to express?
Retinaldehyde dehydrogenase, which converts vitamin A to retinoic acid.
What does retinoic acid do?
Upregulation of adhesion molecules on lymphocytes in mesenteric lymph nodes or PP
So they express CCR9 and a4/B7 the ligand for CCl25
Where is all the lymph collected?
Cisterna chyli
Which are immune cells in liver sinuses, important in maintaining food tolerance?
Kuppfer cells
Intraepithelial lymphocytes include?
Tissue resident memory T cells
Innate like and innate lymphocytes: Mucosa associated invariant T cells NK T cells Gamma delta T cells NK cells
Where are dendritic cells?
Lamina propria
Poly Ig receptor binds to?
J chain
