EVOLUTIONARY INFERENCES OF NOVEL SIMIAN T-LYMPHOTROPIC VIRUS TYPE-1 FROM WILD-CAUGHT CHACMA (PAPIO-URSINUS) AND OLIVE BABOONS (PAPIO-ANUBIS)

A serological survey of 22 wild-caught South African (Transvaal) chacm a baboons (Papio ursinus) and eight olive baboons (Papio anubis) from Kenya indicates that 13 P. ursinus and one Fl anubis have antibodies r eacting with human T cell leukemia/lymphoma virus type 1 (HTLV-I) anti gens, whereas three Fl ursinus had a indeterminate reactivity on weste rn blot analysis. With six primer sets specific to either HTLV-l-Simia n T-cell leukemia virus type 1 (STLV-1) or HTLV-2 and encompassing lon g terminal repeat (LTR), gag, pol, env, and tax sequences, polymerase chain reaction was performed on genomic DNA from peripheral blood mono nuclear cells of 18 animals, and the presence of HTLV-1-STLV-1-related viruses was determined in 13 seropositive and three seroindeterminate animals but not in the two HTLV seronegative individuals. Proviral DN A sequences from env (522 bp), pol (120 bp), and complete (755 bp) or partial (514 bp) LTR were determined for three STLV-1-infected P. ursi nus and one Fl anubis. Comparative and phylogenetic analyses revealed that Fl anubis (Pan-486) sequence clusters with one (Pan-1621) of two previously described P anubis STLV-1. Likewise, Fl ursinus viruses (Pu r-529, Pur-539, and Pur-543) form a distinct group, different from all known HTLV-1 but closely affiliated with two STLV-1 strains from Sout h African vervets (Cercopithecus aethiops pygerythrus). This study, re porting the first STLV-1 sequences from wild-caught Fl ursinus and Fl anubis, corroborates the hypothesis of cross-species transmissions of STLV-1 in the wild. Further, phylogenetic analyses indicate that the k nown HTLV-1 strains do not share a common origin with nonhuman primate s STLV in South Africa. (C) 1998 Academic Press.