ANTAGONISTS OR ALTRUISTS - DO VIRAL MUTANTS MODULATE T-CELL RESPONSES

The ability of altered peptide ligands (APLs) to modify or downregulat e T-cell responses in vitro has generated much interest. Recently, it was proposed that viral variants may contain mutations in cytotoxic T lymphocyte (CTL) epitopes that allow mutual antagonism, and that these combine to downregulate the host. immune response. Here, Miles Davenp ort discusses some inherent problems with this simple model and propos es a closer evaluation of the effects of viral competition on host-vir al interactions.