Induction of monocyte procoagulant activity by murine hepatitis virus type 3 parallels disease susceptibility in mice

The murine hepatitis viruses (MHV) are a group of serologically related pathogenic coronaviruses (21, 22) . Infection of mice by MHV may produce a broad spectrum of diseases, including encephalitis, hepatitis, interstitial pneumonitis, nephritis, and enteritis, depending on the serotype of MHV, the age and strain of the mouse, and the route of infection (23) . Murine hepatitis virus type 3 (MHV-3) is a primarily hepatotropic serotype and causes hepatitis when administered intraperitoneally, intracerebrally, intravenously, or orally in susceptible strains of mice (24, 25) . Balb/c and DBA/2 mice develop acute fulminant hepatitis, C3H mice develop a mild chronic disease, and mice of the A strain develop no evidence of hepatitis (26) . The mechanism of resistance to MHV infection in animals is both complex and poorly understood. It has been demonstrated that resistance to fatal MHV infection may be associated with a resistance gene that inhibits MHV replication in macrophages and is also influenced by a susceptibility factor that is related to lymphocytes (26) (27) (28) (29) (30) .