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Serum and peripheral blood leukocytes from the chimpanzees (Pan troglodytes) of the colony of the Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, NIH, were tested for the presence of STLV-I-specific antibodies and proviral DNA. Antibodies were determined by gelatin particle agglutination and Western blot (WB) assays utilizing HTLV-I antigens. Proviral DNA was detected by four PCR assays targeting three different regions of STLV-I genome: the fragments of the env and pol genes and LTR. Twenty of twenty-two DNA samples from WB-positive animals were PCR positive. None of the DNA samples from WB-negative (n = 5) and WB-indeterminate (n = 4) animals was PCR positive. The results of the nested and double nested env PCR tests were fully concordant; the seminested LTR PCR test was much less sensitive. The DNA sequences from the env (483 bp) and the pol (200 bp) genes and LTR (705 bp) were determined for six, two, and two chimpanzee STLV-I isolates, respectively. Phylogenetic analysis revealed that chimpanzee STLV-I isolates can be attributed to three clades. The first of these clades (SS-PTR1/CSA) included STLV-I isolates from the chimpanzees and West African subspecies of African green monkeys (Cercopithecus a. sabaeus). The other clades (S-PTR2 and S-PTR3) included STLV-I isolates only from chimpanzees. However, both S-PTR2 and S-PTR3 clustered together with Central African HTLV-I comprising the human/simian clade (HS-HSA/PTR). This pattern of phylogenetic clustering suggests that interspecies transmission of STLV-I occurred between chimpanzees and African green monkey subspecies as well between chimpanzees and human populations in Central Africa.

The Taq1 polymorphism in the 3' flanking region of the PI gene has been reported to be associated with chronic obstructive pulmonary disease (COPD). We have studied the frequency of the Taq1 polymorphism in 117 Kuwaiti Arabs and 110 Russians using PCR/RFLP. The frequency of this polymorphism was found to be 0.235 in the Arabs and 0.027 in the Russians. Such a striking difference in allele frequencies could be due to a 'founder effect' in the Kuwaiti population. However: it may also be that this mutation provides a selective advantage, thus accounting for its fixation at a rather high frequency in some populations. Our results suggest that ethnic composition is a very important factor which should be taken into consideration when studying the association of the Taq1 polymorphism with COPD.