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

Abstract

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.

SIVcpz from a naturally infected Cameroonian chimpanzee: Biological and genetic comparison with HIV‐1 N

“…Similarly, current evidence indicate that HIV-2 derives from another primate lentivirus, the SIVsm [4]. Besides SIVsm and SIVcpz, at least ten other primate lentiviruses are present in different African non-human primates, and some of them, such as SIVagms, are abundant and widely spread in sub-Saharan Africa [19]. Thus far, only viruses related to SIVsm and SIVcpz have been identified in humans.…”

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

“…Interestingly, each subspecies is infected by species-specific virus strains, referred to as SIVagm-gri, SIVagm-ver, SIVagm-tan, and SIVagm-sab, respectively. Differences between viruses infecting one AGM subspecies are always less than interspecies variations, and phylogenetic analyses for env nucleotidic or protein sequences have confirmed these observations (1,3,22,29,38,39,45). Together, these findings suggest that the four subspecies-specific SIVagm strains have evolved coincidently with their natural hosts and have diverged from a common ancestor.…”

“…Genetic follow-up of an SIVagm infection in its natural host has shown a limited variability of viral sequences (4), even for the socalled variable regions of the external envelope glycoprotein, and cannot account for the observed diversity. Amino acid identity reported for four SIVagm-tan isolates by Müller et al (45) was thought to reflect viral diversity within the whole AGM subspecies, as these viruses were recovered from monkeys living in distant geographical areas. Our data indicate that the same extent of diversity is found within sympatric populations.…”

An African green monkey lacking peripheral CD4 lymphocytes that retains helper T cell activity and coexists with SIVagm

“…V3, V4 and V5 designate variable regions. The putative CD4 binding site and HIV-1 V3 loop equivalent were as described previously [16,26]. The sequences of the references were obtained from the DNA data bank of Japan (DDBJ): ZA40 (AF015906), ZA358 (AF015905), IPR806 (AF015907), IPR859 (AF015908) and IPR1185 (AF015809) [30]; ver1 (U04003) and ver2 (U04004) [31]; ver155 (M29975) [32]; VER266 (U10896) and VER385 (U10898) [33]; 9063 (L40990) [34]; ver3 (M30931) [35]; and TYO1 (X07805) [1].…”