mucosal immunity Flashcards
what does the GI epithelial barrier do
detects luminal contents and recognises commensal microbes as ‘good bacteria’ from pathogens that require immune response - payer’s patches/M cells
what does the GI mucosa exert
tolerance
tolerance - where are the immune cells
in lamina propia
in specialised cell types -> intra-epithelial T cells
what is develop self-tolerance
non-responsiveness to self antigens
develop exogenous tolerance
non-responsiveness to an enormous array of newly encountered environmental antigens (food and microbes)
what is develop an effective immune response
elimination or control of infections, allergic and noxious agents
what’s the impact of immune cells on IECs and microbiota
- promote barrier repair (cytokines - ILC)
- promote mucin production and AMP secretion
- macrophage and T reg derived mediators - stimulates repair
- impact on permeability
what does immune responses to commensal bacteria (tolerance) and pathogens (active immunity) allow
efficient sampling of particular antigens and deliver to APC (pathogen)
what are lamina propia and dendritic cells important for
directing the functions of T cells
what 3 signals are involved in the interaction between dendritic cells and T cells
MHC - peptide - TCR
CD80-CD28
cytokine
how is gut homeostasis maintained
by balanced T cell responses - T helper cells = T regulatory cells
what do macrophages involve
- phagocytic, ingest and kill foreign micro-organisms
- 1st line of defence in gut
- sampling of particular antigens
- secrete cytokines
- professional APCs to modulate adaptive immune response
what are IELs (intraepithelial lymphocytes)
lymphocytes that lie within the epithelial lining of gut - CD8+ T cells
what does IgA do as a B cell immune response in the gut
binds to immune cells impacting their function
antimicrobial
neutralises toxins
cross talk with microbiota - tolerance
what do cytokines do in B cell immune responses in gut
finely tune immune response - pro inflammatory and anti-inflammatory cytokines
- small proteins - 2 subunits, shared between cytokines
