Antigenic analysis of rabies and Mokola virus from Zimbabwe using monoclonal antibodies.

Eighteen strains of virus were recovered by tissue culture techniques from 20 samples of mouse brain received from Harare, Zimbabwe, and typed with monoclonal antibodies at The Wistar Institute. On the basis of reactivity with these monoclonal antibodies specific for rabies and rabies-related viruses, seven strains were identified as Mokola viruses, and the remaining 11, as rabies viruses. Seventeen of 36 monoclonal antibodies against the nucleocapsid antigen reacted with the Mokola strains, but none of 42 monoclonal antibodies against the glycoprotein that neutralized rabies virus was active against Mokola strains. Mokola virus was, however, neutralized by two monoclonal antibodies produced from mice immunized with Mokola, by a specific anti-Mokola serum prepared in rabbits, and to a lesser extent, by three polyclonal high titer antirabies sera of human or rabbit origin. Immunization of mice with a rabies vaccine (antigenic value, 10 international units) at a concentration 30-fold high than that necessary for complete protection against homologous challenge with rabies virus was not protective against Mokola infection. No cross-reactivity between Mokola and rabies viruses was seen with cytotoxic T lymphocytes.