Molecular and phylogenetic analyses of 16 novel simian T cell leukemia virus type 1 from Africa: Close relationship of STLV-1 from Allenopithecus nigroviridis to HTLV-1 subtype B strains

A serological survey searching for antibodies reacting with human T-cell le ukemia virus type 1 (HTLV-1) antigens was performed on a series of 263 sera /plasma obtained from 34 monkey species or subspecies, originating from dif ferent parts of Africa. Among them, 34 samples exhibited a typical HTLV-1 W estern blot pattern. Polymerase chain reaction was performed with three pri mer sets specific either to HTLV-1/STLV-1 or HTLV-2 and encompassing gag, p ot, and tax sequences, on genomic DNA from peripheral blood mononuclear cel ls of 31 animals. The presence of HTLV-1/simian T-cell leukemia virus type 1 (STLV-1) related viruses was determined in the 21 HTLV-1 seropositive ani mals tested but riot in the 10 HTLV-1 seronegative individuals. Proviral DN A sequences from the complete LTR (750 bp) and a portion of the env gene (5 22 bp) were determined for 16 new STLV-1 strains; some of them originating from species for which no STLV-1 molecular data were available as Allenopit hecus nigroviridis and Cercopithecus nictitans. Comparative and phylogeneti c analyses revealed that these 16 new sequences belong to five different mo lecular groups. The A. nigroviridis STLV-1 strains exhibited a very strong nucleotide similarity with HTLV-1 of the subtype B. Furthermore, four novel STLV-1, found in Cercocebus torquatus, C. m. mona, C. nictitans, and Chlor ocebus aethipos, were identical to each other and to a previously described Papio anubis STLV-1 strain (PAN 503) originating from the same primate cen ter in Cameroon. Our data extend the range of the African primates who coul d be permissive and/or harbor naturally STLV-1 and provide new evidences of cross-transmission of African STLV-1 between different monkey species livi ng in the same environment and also of STLV-1 transmissions from some monke ys to humans in Central Africa. (C) 2001 Academic Press.