Immune tolerance : Immune tolerance The other side of the coin. Slide 2: cattle of dizygotic twin Immune tolerance : Definition: A type of specific unresponsiveness to an antigen induced by the exposure of specific lymphocytes to that antigen, but response to other antigens normally.
Tolerogens: antigens that induce tolerance Immune tolerance : General features of Immunologic tolerance
Tolerance is antigenic specific and results from the recognition of antigens by specific lymphocytes.
Normal individuals are tolerant of their own antigens(self antigen)----- Self-tolerance.
Foreign antigens may be administered in ways that preferentially inhibit immune response by inducing tolerance in specific lymphocytes---antigen induction. Difference of Immuologic tolerance & immunodeficiency, immunosuppression : Difference of Immuologic tolerance & immunodeficiency, immunosuppression Immunodeficiency: any condition in which there is deficiency in the production of humoral and /or cell-mediated immunity---non-specificity to Ag
Immunosuppression: The suppression of immune responses to antigens. This can be achieved by various means, including physical, chemical----non-specificity to Ag Slide 6: Experiment of Medawar on immunologic tolerance Mechanism of Immunologic Tolerance : Mechanism of Immunologic Tolerance Central tolerance
Peripheral tolerance Central tolerance : Central tolerance Central tolerance occurs in the central lymphoid organs as a consequence of immature self-reactive lymphocytes recognizing ubiquitous self-antigen. Peripheral tolerance : Peripheral tolerance Peripheral tolerance was induced in peripheral organs as a result of mature self-reactive lymphocytes encountering tissue-specific self antigens under particular conditions Central tolerance : Central tolerance Clonal deletion (apoptotic cell death)
During maturation of lymphocytes in the thymus for T cell or in the bone marrow for B maturation, immature lymphocytes that recognize ubiquitous self-antigen with high affinity are deleted by negative selection Clonal deletion:negative selection of T cells in the thymus : Clonal deletion:negative selection of T cells in the thymus Negative selection of B cells inbone marrow : Negative selection of B cells inbone marrow Peripheral tolerance : Peripheral tolerance Clonal anergy
functional inactivation without cell death: lack co-stimulatory signal To induce immunologic tolerance : To induce immunologic tolerance Prevent the rejection of organ allografts and xenografts
Treat autoimmune diseases
Treat allergic diseases To terminate immunologic tolerance : To terminate immunologic tolerance To treat tumor
enhance first signal or second signal
To treat infection diseases