THE EXPRESSION OF SELF ANTIGENIC DETERMINANTS - IMPLICATIONS FOR TOLERANCE AND AUTOIMMUNITY

T lymphocytes respond to small peptides in the context of major histoc ompatibility molecules and a host of other cell-surface proteins on an tigen-presenting cells. By design, therefore, T-cell responses are dep endent on the efficient and accurate processing of both foreign and se lf peptides by antigen-presenting cells. This review examines the func tions of T cells that may be specific for self peptides processed and presented under less than ideal conditions or outside the normal pathw ays of antigen processing. Do these T cells survive selection events a nd remain in the repertoire of normal lymphocytes? Moreover, can these cells become activated and are they important in the pathogenesis of autoimmunity?