Introduction

Abstract

I want to begin by talking about some of the questions I find interesting. What we are talking about is how the T cell receptor, MHC and antigen get together and signal a T cell to become activated. The first question is whether the T cell receptor and MHC bind in a single orientation I don’t mean a given T cell and a given MHC antigen but all T cells and all MHC antigens? The receptor and ligand interactions always take place in a certain orientation. Second, what role do the CD4 or CD8 play and how do they play it? Third, what is MLS considered in the broader sense of all of those interesting non-antigens that seem to shape the repertoire by deletion in the thymus? In general and broader terms, how does the T cell receptor repertoire play a role in autoimmunity? I will try and deal with that in my talk. Another question is, are CD4 functional subsets relevant in autoimmunity, in fact do they even exist, and finally, what are the T cell autoantigens — what the T cell recognizes as autoantigens and tissues? I would first like to consider some of the players — TCR alpha beta, MHC class I and II antigen in the form of a peptide, CD8 and CD4 and the products of MLS loci, the question is how do they all fit together?