Extensive genetic variability of simian immunodeficiency virus from African green monkeys

High simian immunodeficiency virus (SIV) seroprevalence rates have been reported in the different African green monkey (AGM) subspecies. Genetic diversity of these viruses far exceeds the diversity observed in the other lentivirus-infected human and nonhuman primates and is thought to reflect ancient introduction of SIV in the AGM population. We investigate here genetic diversity of SIVagm in wild-living AGM populations from the same geographical locale (i.e., sympatric population) in Senegal. For 11 new strains, we PCR amplified and sequenced two regions of the genome spanning the first tat exon and part of the transmembrane glycoprotein. Phylogenetic analysis of these sequences shows that viruses found in sympatric populations cluster into distinct lineages, with at least two distinct genotypes in each troop. These data strongly suggest an ancient introduction of these divergent viruses in the AGM population.

mentioning

confidence: 74%

Genetic diversity of simian immunodeficiency viruses from West African green monkeys: evidence of multiple genotypes within populations from the same geographical locale

Bibollet-Ruche¹,

Brengues²,

Galat‐Luong³

et al. 1997

“…Given the potential for rapid evolution of RNA viruses (32), the high incidence of SIVagm infection may provide fertile ground for substantial genetic variation. Genetic heterogeneity among SIVagm isolates was shown by previous work from our laboratory and others (7,14,18,20), based on restriction endonuclease mapping, cross-hybridization, and limited nucleotide sequence data. In this report, we demonstrate that the sequence variability of SIVagm isolates exceeds that reported for isolates of HIV-1, HIV-2, and SIVmac.…”

mentioning

confidence: 77%

Simian immunodeficiency viruses from African green monkeys display unusual genetic diversity

Johnson

Fomsgaard

Allan

et al. 1990

African green monkeys are asymptomatic carriers of simian immunodeficiency viruses (SIV), commonly called SIVagm. As many as 50% of African green monkeys in the wild may be SIV seropositive. This high seroprevalence rate and the potential for genetic variation of lentiviruses suggested to us that African green monkeys may harbor widely differing genotypes of SIVagm. To investigate this hypothesis, we determined the entire nucleotide sequence of an infectious proviral molecular clone of SIVagm (155-4) and partial sequences (long terminal repeat and Gag) of three other distinct SIVagm isolates (90, gri-1, and ver-l). Comparisons among the SIVagm isolates revealed extreme diversity at the nucleotide and amino acid levels. Long terminal repeat nucleotide sequences varied up to 35% and Gag protein sequences varied up to 30%. The variability among SIVagm isolates exceeded the variability among any other group of primate lentiviruses. Our data suggest that SIVagm has been in the African green monkey population for a long time and may be the oldest primate lentivirus group in existence.

“…SIVs from AGMs were first considered to be only one group, characterized by an extremely high degree of genetic divergence (5,19,20,34,42). The significance of natural variability of SIVagm, however, was difficult to assess because the existence of different AGM species has only recently been considered (1).…”

mentioning

confidence: 99%

Simian immunodeficiency viruses from central and western Africa: evidence for a new species-specific lentivirus in tantalus monkeys

Müller

Saksena

Nerrienet

et al. 1993

119

Although up to 50% of African green monkeys (AGMs) are infected by simian immunodeficiency viruses (SIV) in their natural habitat, they remain asymptomatic carriers of these lentiviruses. They provide an attractive model to study not only the origin but also the link among genetic variation, host-virus adaptation, and pathogenicity of primate lentiviruses. SIVagm have been isolated from three species of AGM: the vervet (Cercopithecus pygerythrus), the grivet (Cercopithecus aethiops), and the sabaeus (Cercopithecus sabaeus) monkey. We studied four new SIVagm isolates from a fourth AGM species, the tantalus monkey (Cercopithecus tantalus), caught in the Central African Republic, and four new isolates from feral sabaeus monkeys from Senegal. Antigenic properties and partial env sequences were used to evaluate the diversity among these isolates. Alignment of env sequences in SIVagm isolated from tantalus and sabaeus monkeys permitted detailed mapping of the variable and conserved domains in the external glycoprotein. Genetic distances indicated that SIVagm isolates from tantalus monkeys are the most divergent among SIVagm in feral AGMs in Africa. The fact that AGMs are infected by four distinct lentiviruses, each specific for a single AGM species, supports the hypothesis of a coevolution of these viruses and their natural hosts and suggests that SIV transmission is a rare event among separated AGM species in the wild.