Meningeal exudate cells in vaccinia meningitis of mice: role of local T cells.

Intracerebral inoculation of vaccinia virus into adult DDD mice produced intensive meningitis several days after infection. The inflammatory reaction could be quantitated by counting cells obtained from this inflammatory lesion. The local virus titer increased until day 5 and subsequently decreased rapidly with time. Concomitant with this titer decrease, numerous meningeal exudate cells appeared in the lesion. The cytotoxic activity of these cells against vaccinia virus infected cells was studied after removal of glass-adherent cells. The results showed that these meningeal exudate cells possessed cytotoxic activity against the virus-infected cells and moreover inhibited plaque formation by vaccinia virus. The magnitude of this activity was much larger than that of spleen cells obtained from the same animals. After treatment with antithymocyte serum, or with antitheta serum plus complement, the meningeal cells lost their inhibitory activity, suggesting that the cells which exerted the effect were mainly T lymphocytes. The meningeal exudate cells obtained on day 7 postinfection were further characterized. A greater part, approximately 80%, of the cell population was composed of theta-positive cells. Less than 1% carried immunoglobulin, 7% possessed neither theta antigen nor immunoglobulin on the surface, and 12% represented glass-adherent cells.