The study of antigen-specific, MHC restricted T cell interactions has been a major focus of our laboratory. This project addresses three aspects of MHC restricted antigen-presentation to T lymphocytes. 1. The nature of processed antigens and their membrane display on antigen-presenting cells. 2. The manipulation of antigens and antigen-presentation to increase immunogenicity. 3. The role of non-MHC encoded structures in antigen- presentation and cell-cell interaction. These issues will be investigated with defined antigens both in vivo and in vitro, the latter with transformed clones of functional specific T cells in conjunction with cloned antigen-presenting cells and model membranes.