Protective effects against simian immunodeficiency virus agm (SIVagm) infection in cynomolgus monkeys immunized with a recombinant vaccinia virus expressing the SIVagm envelope gene

Protective immunity induced by a recombinant vaccinia virus expressing the envelope (Env) protein of a simian immunodeficiency virus strain, SIVagm, ( SEN-RVV), was evaluated in cynomolgus monkeys (Macaca fascicularis). Three monkeys were immunized twice with SEN-RVV and boostered with the purified S IVagm Env protein. These monkeys developed high titers of anti-SIVagm Env a ntibody, especially after boostering. After challenge with polyclonal SIVag m, no virus was recovered from two of the monkeys and no provirus DNA was d etected in one of these two. After autopsy, however, proviral DNA was detec ted in the spleen of this monkey. These results suggest that this immunizat ion regimen could not completely protect the monkeys from SIV infection but that it did reduce the replicability of the challenged virus. (C) 1999 Els evier Science Ltd. All rights reserved.