Highly divergent molecular variants of human T-lymphotropic virus type I from isolated populations in Papua New Guinea and the Solomon Islands.
To determine the molecular genetic relationship between Melanesian strains of human T-lymphotropic virus type I (HTLV-I) and cosmopolitan prototype HTLV-I, we amplified by PCR, then cloned, and sequenced a 522-base-pair region of the HTLV-I env gene in DNA extracted from uncultured (fresh) and cultured peripheral blood mononuclear cells obtained from six seropositive Melanesian Papua New Guineans and Solomon Islanders, including a Solomon Islander with HTLV-I myeloneuropathy. Unlike isolates of HTLV-I from Japan, the West Indies, the Americas, and Africa, which share greater than or equal to 97% sequence homology, the Melanesian strains of HTLV-I were only 91.8%-92.5% identical with a prototype Japanese HTLV-IATK-1. The nucleotide sequence of proviral DNA from the Solomon Islander with HTLV-I myeloneuropathy also diverged markedly from that of HTLV-I isolated from Japanese patients with HTLV-I-associated myelopathy and from Jamaican patients with tropical spastic paraparesis, suggesting that these variant viruses are capable of causing disease. The HTLV-I variants from Papua New Guineans, in turn, differed by nearly 4% from the Melanesian variants from Solomon Islanders, indicating the existence of another HTLV-I quasi-species. By contrast, HTLV-I strains from two residents of Bellona Island, a Polynesian Outlier within the Solomon Islands, were closely related to cosmopolitan prototype HTLV-I (greater than or equal to 97% sequence identity), suggesting recent introduction, possibly during this century. These findings are consistent with a proto-Melanesian HTLV-I strain of archaic presence, which evolved independently of contemporary cosmopolitan strains, and pose new questions about the origin and global dissemination of HTLV-I.
Gessian
A
A
Laboratory of Tumor Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Yanagihara
R
R
Franchini
G
G
Garruto
R M
RM
Jenkins
C L
CL
Ajdukiewicz
A B
AB
Gallo
R C
RC
Gajdusek
D C
DC
D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D015686:Gene Products, env / Q000235:genetics; D005814:Genes, Viral; D015752:Genes, env; D014644:Genetic Variation; D015368:Human T-lymphotropic virus 1 / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008542:Melanesia; D008875:Middle Aged; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D010219:Papua New Guinea; D016133:Polymerase Chain Reaction / Q000379:methods; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid
D004279:DNA, Viral; D015686:Gene Products, env; D015345:Oligonucleotide Probes