HIV-2287 is a viral isolate derived from in vivo passage 2 of HIV-2EHO in Macaca nemestrina. Part of this experiment was to evaluate the pathogenic potential of this virus in other macaque species. Two M. mulatta and two M. fascicularis were inoculated with 5,000 TCID intravenously. The two M. mulatta became infected at very low levels and did not show any depletion of the CD4+ cell population. However, the two M. fascicularis became infected at higher levels in the peripheral blood, and both showed dramatic loss of the CD4+ cell population, one becoming virtually depleted within 4 weeks post-inoculation. This species variation warrants more investigation. Another part of this project is evaluation of the infectivity and pathogenesis of other lentivirus isolates. A lymph node had been isolated from another macaque that was part of the in vivo passage of HIV-2EHO (passage 3). A viral isolate recovered from this lymph node was inoculated into one M. nemestrina as part of this project. This isolate produced infection and CD4+ cell depletion in a time frame comparable to the HIV-2287. This may expand the available pathogenic isolates for future research.