Immunology Flashcards
in a systemic immunoglobulin response, which 3 Igs are the most abundant?
IgG = most abundant, then IgM, then IgA
in an intestinal Immunglobulin response, which 3 Igs are the most abundant?
IgA= most abundant, then IgM, then IgG
how many subunits does IgM have?
5- it is a pentamer
what is IgA present in?
breast milk and tears
how does IgA mediate mucosal immunity?
agglutinates and neutralises pathogens in the lumen and prevents colonisation on epithelial surface
in what form is IgA secreted
as dimers joined by a j-chain which is later internalised
where are many immune cells found in the GI tract?
Peyer’s Patches
once B cells produce IgA, where do they travel to?
travel to mesenteric lymph nodes, then thoracic duct, then back into small bowel where they undergo terminal differentiation into plasma cells
what molecules help return b-cells to gut?
a4B7-integrin bringing to MAdCAM-1
where are intestinal T lymphocytes principally produced in? (2)
- organised gut associated lymphoid tissue (GALT)
2. lamina propria -surface epithelium
what is an example of GALT?
Peyer’s patches
what cells does the lamina propria contain?
CD4 cells
what are the lymphocytes found in the surface epithelium referred to as and what are the most abundant?
intraepithelial lymphocytes (IELs) & CD8 cells
where does T cell sensitisation occur in?
Peyer’s patches
after T cells become sensitised in Peter’s patches, where do they go?
pass through mesenteric lymph nodes > thoracic duct > back to gut where end up in lamina propria or epithelium
