Virus-specific T cells in the central nervous system following infection with an avirulent neurotropic mouse hepatitis virus.

Intracerebral infection of mice with the neurotropic JHM strain of mouse hepatitis virus usually results in a fatal encephalomyelitis. However, infection with the neutralization resistant mutant, 2.2/7.2-V-2, results in inflammatory cell infiltration of the central nervous system with no apparent clinical symptoms, while conferring resistance to subsequent challenge with a lethal dose of wild type JHMV. The mononuclear cells infiltrating the brains of JHMV variant 2.2/7.2-V-2 infected mice were isolated and characterized. Virus-specific T cells which proliferated in response to JHMV antigen and produced both IL-2 and IFN-g were present among mononuclear cells infiltrating the brain as early as day 5 post-infection. The results suggest that the local immune response within the CNS may be important in dictating the outcome of disease following infections with neurotropic viruses.