Persistent infection of baboons and rhesus monkeys with different strains of HIV-2.

HIV-2 infection of eight rhesus macaques and two baboons was studied. Most animals were preselected for HIV-2 inoculation by testing their peripheral blood mononuclear cells (PBMC) for susceptibility to virus isolates from the Ivory Coast. The virus strains used (HIV-2UC2, HIV-2UC3, and HIV-2UC7) were also chosen by in vitro screening in PBMC for high replicating ability and cytopathicity. All the animals seroconverted within 2-4 weeks of infection and remained seropositive throughout the duration of the study. One macaque was sacrificed after 2 years, suffering from diarrhea and weight loss, and one baboon died of non-HIV-related causes. The remaining animals are asymptomatic, with normal CD4/CD8 ratios. Virus has been recovered from most animals, and persistent HIV-2 replication has been noted in three macaques and a baboon. Host range studies in T, B, and monocyte cell lines showed little or no differences between isolates obtained after inoculation and the original virus inoculum. However, isolates from the macaque that showed clinical symptoms were more cytopathic as reflected by plaque formation in MT-4 cells. The HIV-2-infected macaque or baboon could be useful as an animal model for elucidating the mechanisms of HIV pathogenesis and for evaluating potential antiviral therapies and vaccines.