CHARACTERIZATION OF NEW SIMIAN FOAMY VIRUSES FROM AFRICAN NONHUMAN-PRIMATES

Simian foamy viruses (SFV) are exogenous retroviruses present in most ii not ail nonhuman primate species. Baboons and other African monkey species are known to harbor SFVs, yet there is presently no data in re gard to their genetic relationship. Here we studied SFVs from baboons as compared to other SFVs isolated from a Hamlyn's guenon, a patas mon key, and a vervet. By Western blot analysis, the gag precursor protein s (p74/p70) were detected from all SFVs. In addition, the envelope gly coproteins from a vervet isolate (SFV-Agm2) were comparable in size to the env precursor gp130, the exterior glycoprotein (gp70), and the tr ansmembrane protein (gp48) as detected by lentil lectin binding and ra dioimmunoprecipitation (RIPA). Molecular comparison of PCR amplified p roducts from pol and LTR regions of each SFV demonstrated a close rela tionship among baboon SFVs while SFVs from patas, Hamlyn's guenon, and vervet clustered together. The baboon viruses only varied by 4% among each other in the LTR region; however, as much as 26% variation was n oted when compared to the other African monkey SFVs. To determine the prevalence rate of SFV-Bab in our baboon colony, we employed both West ern blotting and PCR analysis. Antibodies to SFV gag precursor protein s were seen in 7 of 10 infants; however, none were positive by PCR, su ggesting that these infants were virus negative and that their antibod ies were maternal in origin. Only one juvenile (1/10) and all adults ( 38/38) were infected with SFV. Taken together these results suggest th at SFVs have arisen and diverged along with the evolution of their nat ural hosts. Furthermore, the high prevalence rates to SFV seen in adul t baboons strongly suggest a sexual or oral routes of transmission. (C ) 1997 Academic Press.