Question

Many cells in the human body have proteins on the surface that are able to interact with the receptors of helper T cells. Explain the mechanisms and why it is that such an interaction or signal does not usually result in an autoimmune reaction? 10 points at least 10lines

Answer 1

Autoimmune reaction is the immune responses of an organism against its own healthy cells and tissues.

The mechanisms which prevent such immune responses by the T cells and B cells are divided into Central tolerance and peripheral tolerance.

Central tolerance, also known as negative selection.  Negative selection obliterates the T cells that bind too strongly to self-antigens expressed on MHC molecules. This occurs in primary lymphoid organs such as the bone marrow and the thymus

Peripheral tolerance occurs once developing immune cells exit primary lymphoid organs. It takes place in the immune periphery and ensures that self-reactive T and B cells which escaped central tolerance do not cause autoimmunity. The mechanisms of peripheral tolerance include inactivation of the self-reactive T cells by clonal deletion, conversion to regulatory T cells (Tregs) or induction of anergy.