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.

The variety of factors known to cause a change in the susceptibility of a host to a standard virus preparation must then be analyzed in terms of both the host itself and the virus population. In the present instance one might argue that C3H cells are continually resistant to MHV(PRI) and that only when, under some yet unknown conditions, the virus is converted to the MHV(C3H) type does the resistant C3H host or its cells succumb. However, recent unpublished work by D. O. Willenborg et al. on a cortisone-induced change in the susceptibility of C~H mice (9) weighs heavily against this explanation. On the other hand the report by Kantoch and Bang (10) that resistant cells in culture may be made more susceptible by the addition of an extract of susceptible cells can also be interpreted as an increase in the capacity of these resistant cells to produce virus which is capable of killing resistant cells.