Rapid CD4(+) T-cell loss induced by human immunodeficiency virus type 1(NC) in uninfected and previously infected chimpanzees

To investigate the pathogenicity of a virus originating in a chimpanzee wit h AIDS (C499), two chimpanzees were inoculated with a plasma-derived isolat e termed human immunodeficiency virus type 1(NC) (HIV-1(NC)). A previously uninfected chimpanzee, C534, experienced rapid peripheral CD4(+) T-cell los s to fewer than 26 cells/mul by 14 weeks after infection. CD4(+) T-cell dep letion was associated with high plasma HIV-1 loads but a low virus burden i n the peripheral lymph node. The second chimpanzee, C459, infected 13 years previously with HIV-1(LAV), experienced a more protracted course of periph eral CD4(+) T-cell loss after HIV-1(NC) inoculation, resulting in fewer tha n 200 cells/mul by 96 weeks postinoculation. The quantities of viral RNA in the plasma and peripheral lymph node from C459 were below the lower limits of detection prior to inoculation with HIV-1(NC) but were significantly an d persistently increased after superinfection, with HIV-1(NC) representing the predominant viral genotype. These results show that viruses derived fro m C499 are more pathogenic for chimpanzees than any other HIV-1 isolates de scribed to date.