Adaptive Immunity Flashcards
How do T cells contribute to immunity?
Three types, nkc, t helper and t killer cells. Cd4 and cd8 bind antigen on apc via trc. Il2 stimulation proliferation via autocrine signalling to induce clonal expansion.
Direct immune response.
Tk cells recognise altered self and activate apoptosis.
What are antigen presenting cells?
Present antigen via Mhc 2. Dendritic cells found near cell surface Langerhans are resident dcs in skin. Kupffer cells are liver macrophages. And ofc macrophages,
How do B cells produce antibodies?
B cells bind to antigen via ig D B cell receptors. To activate B cells two things are necessary:
- stimulation of bcr with cognate antigen.
-co stimulation from activated th cells TCR.
B cells are activated and mature into plasma cells and B memory cells.
Cytokines secreted from B cells cause plasma cells to secrete antibodies. Mainly igM. Class switch caused by cytokines.
What do antibodies do?
IgA bind to pathogens with 4 binding sites causing them to clump together and preventing movement through tissue.
IgM forms pentameters. This is called AGGLUTINATION.
Antibodies may also act as opsonins
Activate complement pathway
Degranulate mast cells
What are the classes of antigens?
Causes by constant region. IgM agglutination IgA mucosal defence. IgG opsonins IgE mast cell IgD B cell receptor
How does class switch occur?
TNF b: igA
Gamma interferon: ig G
Il4, il13: Ig e
What is adaptive immunity?
Highly specialised response confers lasting immunity through antibody production.
What are granulomas?
Epitheliod macrophages and scattered lymphocyte ball. Occurs as part of granulomalous inflammation.
Occurs when cause if inflammation is difficult to ingest:
- mycobacterium
-foreign bodies
-automimmune
-unknown cause eg chrons or sarcoidosis.
What are giant cells?
When more than one macrophage tries to ingest. Large cytoplasm multiple nuclei.
What stain is used for mycobacterium?
Ziehl- neelson stain is used as the bacterium is acid fast and resists decolourisation by acid.
