Allele-specific alien-driven diversity, immune responsiveness and MHC-restriction.

Synthetic and environmental antigens are presented to T cells in the context of MHC determinants but, for certain antigens, some determinants are more effective than others(1-3), perhaps because they make an optimal or more immunogenic physical association with the antigen(2,3). Here, Randy Mandell and Paul Sondel use the concepts of immune crossreactivity and 'alien' MHC antigens to propose an alternative explanation for allele-specific MHC-restriction of T-cell responses to certain antigens. Such allele-specific, alien-driven diversity may also be relevant to the relationship between MHC determinants and immune response genes.