Enhancement in anti-Semliki Forest virus activity of ds RNA by a muramyl dipeptide

Antiviral activity of an interferon-inducing mycoviral ds RNA against Semliki Forest virus infection was considerably enhanced by N-palmitoylmuramyl-L-alanyl-D-isoglutamine (PMDP), a new muramyl dipeptide. This enhancement in activity was not due to increased production of interferon, but resulted probably from a PMDP-induced increase in nonspecific resistance to infection. These results indicate that a combined treatment with an interferon inducer and muramyl dipeptide may prove highly useful to control effectively viral infections.