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.

Three pools of antiserum were tested for their capacity to neutralize 100 TCIDs0 (tissue culture infective dose, median) of plaque-purified MHV(PRI) and plaque-purified MHV(C3H): (a) antiserum prepared against MHV(PRI) in 1 month old Swiss albino mice; 9.0 X 105 0 * A series of cultures containing 2 )< 10 6 Call cells were inoculated with different concentrations of MHV(PRI). After 1 hr at room temperature they were superinfected with 3.0 X 10 2 TCIDs0 of MHV(C3H) and incubated at 37°C. 20 hr later MHV(C3H) titers were determined by diluting the samples and infecting five C3H tube cultures for each dilution. Results (Table VII) show that the two viruses were antigenically indistinguishable. To test this, Call macrophage cultures were infected with different multiplicities of MHV(PRI), and an hour later, superinfected with a given concentration of MHV(CaH). The The ability to inhibit vesicular stonmtitis virus is taken as a criterion for the presence of interferon. Assays were conducted on monolayers of L cells using the plaque technique.