The human T cell receptor in health and disease.

The T cell antigen receptor (TCR) recognizes antigen in the form of short peptides bound to a major histocompatibility (MHC) molecule. This review provides a synopsis of the current state of knowledge of the structure and function of the receptor and its possible role in human disease. Analysis of the T cell receptor usage of T-cell lines and clones recognizing the same peptide-MHC complex is beginning to shed light onto the structural basis of the TCR-peptide-MHC complex. Also, it is now apparent that there are two mechanisms by which the TCR can interact with the MHC molecule, either through classical peptide interactions or through super-antigens. Finally, we review the role of specific TCRs in human disease. Current evidence in this area is difficult to interpret; however, it is likely that TCR-mediated disease susceptibility exists, and its basis at either a germline or somatic level will soon be clarified.