Degeneracy in T-cell antigen recognition - implications for the pathogenesis of autoimmune diseases

T-cells recognize by their T-cell receptor (TCR) short peptides presented b y major histocompatibility complex (MHC) molecules. Based on functional and structural data. it has become widely accepted that this interaction is hi ghly flexible thus allowing a specific TCR to interact with a broad range o f different peptide ligands. Although cross-reactivity is essential for sel ection and maintenance of the T-cell repertoire. it also carries the danger of inducing autoreactivity following protective immune responses. This hyp othesis has been supported by a large number of findings in vitro and in vi vo experimental systems. Here we discuss recent findings on cross-recogniti on of T-cells and provide a new experimental approach to address specificit y and cross-reactivity in autoimmune disorders. (C) 2000 Elsevier Science B .V. All rights reserved.