Specificity of the Inflammatory Response in Viral Encephalitis

The viral-induced perivascular inflammatory response in Sindbis virus encephalitis of mice was shown to be immunologically specific. Mice were inoculated intracerebrally with Sindbis virus, and 24 hr later a single dose of cyclophosphamide was given which ablated the inflammatory response. 3 days after virus inoculation, cells and/or sera from specifically and nonspecifically sensitized donor mice were given, and the inflammatory reactions, virus content, and antibody response of recipients were examined 5 days later. Reconstitution of the viral inflammatory response required virus-specific sensitized lymph node cells and was enhanced when these lymph node cells were combined with bone marrow cells. Reconstitution was not achieved with Sindbis virus immune serum even when combined with nonspecifically sensitized cells. Combination of immune serum with Sindbis virus-sensitized cells did not produce an accentuation of the reaction. In distinction, reconstitution of the inflammatory reaction surrounding the stab wound was reconstituted with bone marrow cells from mice inoculated with Sindbis virus or control antigens. Reconstitution of the perivascular reaction was associated with a reduction in brain virus content. Although the transfer of Sindbis virus-sensitized lymph node cells and bone marrow cells resulted in the limited production of neutralizing antibody in the immunosuppressed recipient, the reduction in virus was significantly greater with the transfers of Sindbis virus-sensitized lymph node cells than with the passive transfer of immune serum alone.