Final answer:
T cells recognize antigens through antigen presentation and can become anergic to prevent autoimmunity.
Step-by-step explanation:
T cells recognize antigens with their antigen receptor, a complex of two protein chains on their surface. They do not recognize self-antigens, however, but only processed antigen presented on their surfaces in a binding groove of a major histocompatibility complex (MHC) molecule.
Antigen processing is a mechanism where antigens are enzymatically cleaved into smaller pieces and then presented on the cell's surface with an MHC molecule. This presentation, known as antigen presentation, allows T cells to recognize the antigens and initiate an immune response.
T cell anergy, or tolerance, can be generated when self-reactive T cells that escape the thymus lack the co-stimulatory signal required for activation. This lack of activation prevents autoimmune activation. Additionally, regulatory T cells play a role in peripheral tolerance by inhibiting the activation and function of self-reactive T cells and by secreting anti-inflammatory cytokines.