ISOLATION AND CHARACTERIZATION OF SIMIAN IMMUNODEFICIENCY VIRUS FROM AFRICAN WHITE-CROWNED MANGABEY MONKEYS (CERCOCEBUS-TORQUATUS-LUNULATUS)

Forty-eight of 236 sera from seven species of African non-human primates in Kenya, including those of white-crowned mangabey monkeys (Cercocebus torquatus lunulatus) had antibodies to simian immunodeficiency viruses (SIVs). Isolates of simian lentivirus were obtained from seropositive white-crowned mangabey monkeys which are indigenous in West Africa. This virus, designated as SIV(WCM), appeared morphologically similar to HIV by electron microscopy, showed Mg2+-dependent reverse transcriptase activity, and induced cytopathic effects in human CD 4-positive cells. Western blotting analysis revealed that env products of SIV(WCM) cross-reacted with those of SIV(AGM) more strongly than with those of HIV-I and SIV(MAC), and clear hybridization bands were detected with an SIV(AGM) probe. For comparison of the virus sequence with those of other primate lentiviruses, part of the pol gene and the long terminal repeats (LTRs) were amplified and cloned. Sequencing showed that SIV(WCM) isolates were closely related to SIV(AGM) isolates. This study suggested that SIV(AGM) from the Cercopithecus genus and SIV(WCM) from the Cercocebus genus may be members of an SIV group that is genetically distinct from the SIV from a sooty mangabey monkey (SIV(SMM)) of the genus Cercocebus, to which the white-crowned mangabey monkey also belongs.