[Sensitization against the antigens of the brain after experimental vaccinia infection. I. Evidence for cell-mediated immune response to brain-antigens (author's transl)].

Vaccinia virus infection was performed by scarification of the shaved skin (5 times 5 cm2) on the back of Pirbright guinea pigs. The macrophage migration inhibition test was performed with peritonealexudate cells 7, 11, 14 and 21 days after infection. Macrophage migration inhibition occurred after exposure of the cells to whole brain tissue antigen on the 7th, 11th, 14th day after infection (s. table 1). Lymphocyte transformation responses were examined by 14C-2-Thymidin uptake using blood cultures and basic encephalitogenic protein and whole brain tissue extract as antigens. A positive transformation response could be demonstrated from one to 8 weeks after infection (s. table 2). The specificity of the transformation response to brain antigen was established using control cultures stimulated with PHA or PPD. In no case stimulation occured with PPD. Stimulation with PHA was not altered. On the other hand the spontaneous lymphocyte transformation was enhanced at one week after infection and lymphocyte cultures exposed to heat inactivated vaccinia virus showed transformation from the 3th week after infection until the end of the observation period (i.e. 8 weeks) (s. table 2). The reason why cell mediated hypersensitivity to brain antigen is induced following vaccinia infection remains unknown. The most probable among several possible mechanisms seem a) the induction of virus-specific antigens on the surface of infected cells or b) the release of brain specific antigen through virus infection.