A chimpanzee rhadinovirus sequence related to Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8: increased detection after HIV-1 infection in the absence of disease

Objective: To look for a virus related to Kaposi's sarcoma-associated herpe svirus (KSHV) or human herpesvirus 8 (HHV8) in chimpanzees and to investiga te phylogenetic and biological similarities to KSHV. Methods: Peripheral blood mononuclear cell (PBMC) DNA samples from chimpanz ees (Pan troglodytes troglodytes) were screened with newly designed consens us oligonucleotide primers for the DNA polymerase gene of KSHV-related gamm a2-herpes-viruses (rhadinoviruses). Samples from HIV-l-infected and -uninfe cted chimpanzees were screened with virus-specific primers. Antibodies to K SHV structural and latent antigens were measured by immunofluorescence, enz yme-linked immunosorbent assay (ELISA) and Western blot. Results: We identified 972 base pairs (bp) of a new viral DNA polymerase se quence with 81.6% (nucleotides) and 93.2% (protein) identity to that of KSH V/HHV8. It was detected in 15/37 (41%) animals experimentally infected with HIV-1, but only in one out of 30 uninfected animals (P < 0.001). Antibodie s were found by immunofluorescence to structural, but not latent, KSHV anti gens in nearly all HIV-l-infected and uninfected animals. Conclusion: Like man and two other Old World primate species, chimpanzees h arbour a virus closely related to KSHV/HHV8, termed Pan troglodytes rhadino virus-1 (PtRV-1). Like KSHV, PtRV-1 is more easily detected by polymerase c hain reaction (PCR) in the PBMC of HIV-l-infected than of HIV-1-uninfected individuals, suggesting increased viral load. Despite the close phylogeneti c relationship and biological similarities between KSHV and PtRV-1, Kaposi' s sarcoma (KS) has not been reported in HIV-1-infected chimpanzees. PtRV-1 may lack some of the pathogenic determinants of KSHV, or humans and chimpan zees may differ in how they control the infection with their respective rha dinoviruses. (C) 2000 Lippincott Williams & Wilkins.