ORGANS OF IMMUNE MECHANISM免疫机制的细胞和器官课件.ppt

Precipitation (Precipitin) In this test the antigen is in solution. The antibody cross-links antigen molecules in variable proportions, and aggregates (precipitates) form. In this test the antigen is in solution. The antibody cross-links antigen molecules in variable proportions, and aggregates precipitates form Radioimmunoassay (RIA) This method is used for quantitation of antigens or haptens that can be radioactively labeled. It is based on the competition for specific antibody between the labeled (known) and the unlabeled (unknown) concentration of material. Enzyme-Linked Immunosorbent Assay (ELISA) This method can be used for quantization of either antigens or antibodies in patient specimens. It is based on covalently linking an enzyme to a known antigen or antibody, reacting the enzyme linked material with the patients specimen, and then assaying for enzyme activity by adding the substrate of the enzyme. * * CELLS ORGANS OF IMMUNE MECHANISM. Origin structure. IMMUNE CELLS. Fetal liver -------------yolk cells Blood cell precursors. Stem cells reside in bone marrow. Erythroid, myeloid lymphoid series. Lymphocyte populations. T-Lymphocytes (cytotoxic helper T-cells). Precursors differentiate in the thymus. B –Lymphocytes develop in the bone marrow,gut associated lymphoid tissue,spleen and lymph nodes. The ratio of T to B cells is approximately 3:1. T-Cells. Constitute 65-80% of circulating small lymphocytes. Life span is long(months-years). Some (40%) develop in the gut associated lymphoid tissue(GALT)instead of thymus. Precursors differentiate in the thymus mainly. THYMIC EDUCATION. CLONAL DELETION (by apoptosis) Negative selection self tolerance. THYMIC EDUCATION. Positive selection for T cells that react well with self reacting antigens. T cells are produced that are