IN VITRO INTERACTION OF MOUSE HEPATITIS VIRUS AND MACROPHAGES FROM GENETICALLY RESISTANT MICE : II. BIOLOGICAL CHARACTERIZATION OF A VARIANT VIRUS MHV(C(3)H) ISOLATED FROM STOCKS OF MHV(PRI)

Shif, Ilan; Bang, Frederik B.

Since the virulence of a virus is usually multifactorial in both natural and experimental infections, it is of considerable interest to identify a situation in which a single genetic character controls virulence. Susceptibility or resistance to mouse hepatitis virus (MHV) 1 may be controlled by a single genetic character. In turn the genetic resistance of the Call mice to MHV Princeton strain (PRI) may be overcome by a change in the virus and we here report the sudden regularly produced change of MHV(PRI) which is incapable of killing resistant C3H mice or their macrophages to one which regularly kills both the macrophages and the host mice. In the preceding paper (1) we demonstrated that even though resistant cells adsorb the virus, the virus does not develop a fullblown infection in the C~-I system; further, it remains infectious only for the original mouse (PRI) cells even after it has been resident in the resistant (C3H) cells for some 100 hr.