ABSTRACT
Successful viral replication requires complex interactions between viral and host components, which have to be present at the right times, intracellular locations, and concentrations. Host-derived intracellular resistance factors, however, are only beginning to be characterized at the molecular level, although genetic variation in susceptibility to various viral diseases independent of the immune system has been observed in many vertebrate species. Interferon-induced homologs of the murine Mx1 protein exist in vertebrate species ranging from fish to man. When assayed in the same way, the human MxA protein which accumulates in the cytoplasm has a broader antiviral specificity than the murine Mx1 protein: it renders cells resistant not only to influenza A and Thogoto virus, but also to vesicular stomatits virus, measles, Hantaan, La Crosse, and Rift Valley fever virus. The data demonstrate that the murine Mx1 cDNA is capable of transfering heritable specific antiviral resistance to an otherwise susceptible vertebrate host.
