Immunomodulation by HLA class I-derived peptides.

Synthetic peptides corresponding to linear sequences of HLA class I molecules have profound immunomodulatory effects in vitro and in vivo. Recent clinical trials confirm their potential as the therapeutics for transplantation and for a variety of immune-mediated diseases. These peptides also inhibit NK responses in vivo in humans. The importance of the carboxy end of the alpha 1 alpha helix in negative signaling to both T cells and NK cells focuses attention on new targets for immunotherapy.