Immunology Flashcards
Follicle
Site of B-cell localization and proliferation. In outer cortex. Primary follicles are dense and dormant. Secondary follicles have pale central germinal centers and are active.
Medulla
Consists of medullary cords (closely packed lymphocytes and plasma cells) and medullary sinuses. Medullary sinuses communicate with efferent lymphatics and contain reticular cells and macrophages.
Paracortex
Houses T cells. Region of cortex between follicles and medulla. Contains high endothelial venules through which T and B cells enter from blood. Not well developed in patients with DiGeorge syndrome. Paracortex enlarges in an extreme cellular immune response.
HLA subtypes associated with disease
A3 (hemochromatosis), B27 (Psoriatic arthritis, Ankylosing spondylitis, arthritis of Inflammatory bowel disease, Reactive arthritis (formerly Reiter syndrome)), DQ2/DQ8 (Celiac disease), DR2 (Multiple sclerosis, hay fever, SLE, Goodpasture syndrome), DR3 (Diabetes mellitus type I, SLE, Graves disease), DR4 (Rheumatoid arthritis, diabetes mellitus type I), DR5 (Pernicious anemia ->vitamin B12 deficiency, Hashimotos thyroiditis)
Natural killer cells
Use perforin and granzymes to induce apoptosis of virally infected cells and tumor cells. Only lymphocyte member of innate immune system. Activity enhanced by IL-2, IL-12, IFN-B and IFN-A. Induced to kill when exposed to a nonspecific activation signal on target cell and/or to an absence of class I MHC on target cell surface. Also kills via antibody-dependent cell-mediated cytotoxicity (CD16 binds Fc region of bound Ig, activating the NK cell).
Positive selection
Thymic cortex. T cells expressing TCRs capable of binding surface self MHC molecules survive
Negative selection
Medulla. T cells expressing TCRs with high affinity for self antigens undergo apoptosis
Cell surface proteins
FA 206
Hypersensitivity reaction
FA 208 and 209
Autoantibodies
210
Immunosuppressants
FA215
