DEMONSTRATION OF VACCINIA VIRUS ANTIGEN IN BRAINS OF POSTVACCINAL ENCEPHALITIS CASES

Abstract
Five lethal [human] cases of postvaccinal encephalitis (PVE) were examined in attempts to detect the viral antigen by the fluorescent antibody techniques and to isolate the infectious vaccinia virus. Histologically, the brain tissues were characterized by meningoencephalitis, with perivascular infiltrations and inflammatous reactions mainly in leptomininx, choroid plexus and ependyma. By direct immunofluorescence staining, vaccinia virus antigen was found in the brain specimens of 1 case, but not in the other 4 cases. The existence of antigen-antibody complexes was suggested by the deposition of immunoglobulins [Ig] in the brain specimens. After treatment with 3 M NaSCN solution to dissociate the Ig from the complex, the viral antigen was demonstrated in specimens of 2 cases. Localization of viral antigen(s) thus detected coincided with that of meningoencephalitic reactions in the histological examination. Virus isolation on chick embryo chorioallantoic membrane was negative in all cases. Participation of viral pathogenicity in the etiology of PVE is discussed.