MHC-antigen-T cell interactions: an overview.

: We describe the establishment and validation, both at the biochemical and biological levels, of direct assays to measure the interactions between synthetic peptides and purified HLA class II molecules. The results of several independent approaches to define the structural requirements for the interaction of peptide-class II molecules are also described. Such approaches include random screening, sequence analysis, and site-directed mutagenesis. Finally, in vivo data illustrating the possibility that the competition at the level of the interactions between autoantigenic peptides and class II molecules could be a useful tool in the treatment of T cell-mediated autoimmune diseases are presented.