L38 Background T1DM

Tolerance is a state of immunological unresponsiveness, and an [blank_start]adaptive[blank_end] response of lymphocytes. It exists because lymphocytes have [blank_start]self-reactive[blank_end] receptor, as receptors are formed by somatic recombination and sometimes recognise [blank_start]self-tissue[blank_end]. They must be deleted, or controlled by tolerance.

Peripheral Tolerance is the mechanism for controlling self reactive cells that escaped deletion in their early stages. • 3 ways this may occur: 1. Ignorance; lymphocytes are [blank_start]physically[blank_end] separated from low conc. self-antigen at “immune privileged sites” eg the [blank_start]brain, eye, testes, foetus[blank_end]. The sites also produce [blank_start]immunosuppressive cytokines[blank_end]. 2. Anergy; antigen specific non-[blank_start]responsiveness[blank_end], a second signal needed from an [blank_start]APC[blank_end] is not there to activate [blank_start]T cell[blank_end]. 3. Suppression; an active process [blank_start]mediated[blank_end] by a suppressor or regulatory lymphocyte.

Autoimmunity is the breakdown of self tolerance.

Diabetes is a T-cell mediated autoimmune disease.