Identification of a new subgroup of SIVagm in tantalus monkeys

Simian immunodeficiency viruses from African green monkeys (SIVagm) can be classified into three subgroups based upon the species from which they were isolated. The most extensively studied subgroup are composed of SIVagm isolated from vervet monkeys (Cercopithicus pygerythrus). Fewer isolates have been characterized from either grivets (Cercopithicus aethiops) or green monkeys (Cercopithicus sabeus). An additional distinct species of African green monkeys, tantalus monkeys (Cercopithicus tantalus), has not been characterized in terms of SIV infection. A high seroprevalence of SIV-specific antibodies was identified in sera collected from Ugandan tantalus monkeys. SIV was isolated from PBMC (SIVagm/tan), the gag region amplified by polymerase chain reaction, cloned, and sequenced. Based upon gag, SIVagm/tan isolates cluster genetically with other previously recognized SIVagm strains. However, SIVagm from tantalus monkeys forms a distinct genetic subgroup. These data confirm earlier observations of species-specific subtypes of SIVagm viruses and support the hypothesis that these viruses may have coevolved with their host during geographic dispersion throughout Africa.