There is increasing appreciation that T-cell receptors (TCR) display a high degree of
crossreactivity and degeneracy in their recognition of peptide antigens. These findings,
coupled with the division of peptide ligands into antagonists or agonists depending on their
affinity for the TCR, have shed new light on mechanisms of self-tolerance and autoimmunity
and are the subject of this review. We summarize current evidence for two opposing effects
of TCR crossreactivity. These data suggest that TCR crossreactivity of autoreactive T-cells …