Immunomodulatory Function of MHC Peptides

Abstract

Our continuing dependence on long-term broad spectrum immunosuppression, coupled with a growing understanding of the mechanisms mediating the alloimmune response, has led to an increasing focus on the development of alternative, more specific forms of immunotherapy in the hope of inducing transplant tolerance. In recent years it has become apparent that the peptide bound by the MHC molecule plays a major influential role in the initial T cell receptor interaction with the MHC/peptide complex, and also in the subsequent T cell response. There is now extensive experimental evidence in vitro and in vivo, that varying the nature of the bound peptide provides an effective means of manipulating the immune response. It would appear, however, that the role of peptides as immunosuppressants is not limited to the disruption of antigen recognition alone, but rather they may exert their effects through many diverse mechanisms including inhibition of cell cycle progresssion, altered signal transduction and the induction of apoptosis. The potential, therefore, exists that peptides, or compounds derived from them, may represent an exciting new form of immunotherapy.