T lymphocyte-dependent difference in susceptibility between DDD and C3H mice to mouse hepatitis virus, MHV-3.

After intraperitoneal inculation with a virulent mouse hepatitis virus, MHV-3, 50% lethal dose in DDD mice was about 7 log10 higher than that in C3H mice. Histopathologically, splenic lymphocytes especially of the thymus-dependent area were more severely affected in susceptible C3H mice than in DDD mice. In the liver of C3H mice, virus multiplied exponentially after inoculation, attaining 10(6) PFU at moribund stage, while virus multiplication in DDD mice was much less prominent decreasing remarkably at day 5 or later. The virus could multiply in the primary culture of spleen cells from C3H mice but not in those from DDD mice, and cells supporting virus growth seemed to be a theta-positive population of lymphocytes. No difference was observed between the two strains of mice in the ability of peritoneal macrophages to support virus growth in vitro as well as serum interferon levels after infection.