Human T-cell leukemia virus type 1 molecular variants, Vanuatu, Melanesia

Abstract

Four of 391 Ni-Vanuatu women were infected with variants of human T-cell leukemia virus type 1 (HTLV-1) Melanesian subtype C. These strains had env nucleotide sequences approximately 99% similar to each other and diverging from the main molecular subtypes of HTLV-1 by 6% to 9%. These strains were likely introduced during ancient human population movements in Melanesia.

Figure 1

Representative seroreactivity pattern on Western blot that contains a recombinant GD 21 (common to human T-cell leukemia virus type 1 [HTLV-1] and HTLV-2) and 2 synthetic peptides specific for HTLV-1 (MTA-1) and HTLV-2 (K55). Lane 1, HTLV-1–positive control; lane 2, HTLV-2–positive control; lane 3, HTLV-1/2 negative control; lane 4–9, 6 plasma samples from the HTLV-1–positive women of Ambae Island displaying strong reactivity to GD 21 (faint band for VAN 251), to p19 and p24 (faint band for VAN 54), p26, p28, p32, p36 (faint bands for VAN 54 and AWM), and to MTA-1.

Figure 2

Unrooted phylogenetic tree generated by the neighbor-joining method by using the 522-bp fragment of the env gene. Distance matrices were generated with the DNADIST program, using the Kimura 2-parameter method and 5.65 as the transition/transversion ratio. Bootstrap analysis was carried out with 1,000 datasets. The values on the branches indicate frequencies of occurrence for 1,000 trees. The 4 new human T-cell leukemia virus type 1 (HTLV-1) sequences (VAN 54, VAN 136, VAN 251, VAN 335; GenBank accession nos. AY549879, AY549880, AY549881, AY549882) were analyzed with 126 HTLV-1/simian T-cell leukemia virus type 1 (STLV-1) sequences available from the GenBank database. The branch lengths are proportional to the evolutionary distance between the taxa.

Figure A1

Unrooted phylogenetic tree generated by the neighbor-joining method by using the complete fragment of the long terminal repeat (LTR) (755 bp). Distance matrices were generated with the DNADIST program, using the Kimura 2-parameter method and 5.17 as the transition/transversion ratio. Bootstrap analysis was carried out with 1,000 datasets. The values on the branches indicate frequencies of occurrence for 1,000 trees. The 4 new human T-cell leukemia virus type 1 (HTLV-1) sequences (VAN 54, VAN 136, VAN 251, VAN 335; GenBank Accession nos. AY549875, AY549876, AY549877, AY549878) were analyzed with 75 HTLV-1/STLV-1 sequences available from the GenBank database. The branch lengths are proportional to the evolutionary distance between the taxa.