Studies of immune responses during recovery from Sindbis virus encephalitis in selectively reconstituted, thymectomized, lethally irradiated mice.

Recovery from acute Sindbis virus encephalitis was studied in selectively reconstituted, thymectomized, irradiated mice. Intact mice cleared virus from the brain by day 10 and developed inflammation along with immunoglobulin M (IgM) and IgG antibodies 4 to 6 days after infection. Unreconstituted mice died by day 11, with virus still present but decreasing, no detectable antibody, and no evidence of inflammation. Mice reconstituted with bone marrow cells alone produced only IgM antibody and no inflammation, but cleared virus by day 14. Mice reconstituted with sensitized T cells alone cleared virus by day 10, produced very small amounts of antibody, and developed a prompt inflammatory response.