Phylogenetic classification of human T cell leukaemia/lymphoma virus type I genotypes in five major molecular and geographical subtypes

Abstract

Proviral DNA was obtained from ex vivo peripheral blood mononuclear cells of 75 human T cell leukaemia/ lymphoma virus type I (HTLV-I)-infected individuals who were either asymptomatic or had adult T cell leukaemia or tropical spastic paraparesis/HTLV-I-associated myelopathy. Amplified long terminal repeats (LTRs) were analysed for restriction fragment length polymorphisms (RFLPs). The results, together with previously published LTR data (a total of 180 specimens analysed), showed the presence of 12 different RFLP profiles with four major molecular subtypes. Furthermore, a fragment of 413 bp (nucleotides 22 to 434) of the U3/R region was sequenced for 12 new HTLV-I specimens originating from Central and West Africa (8 cases), Iran (1 case), Caribbean (2 cases) and Reunion Island (1 case). Phylogenetic analysis using three different techniques (maximum parsimony, neighbourjoining and UPGMA) comparing these 12 strains (including four new African HTLV-I variants) with the 30 published partial HTLV-I LTR sequences (nt 120 to 434) showed the existence of clusters of molecular variants in discrete geographical areas. The topology of the phylogenetic trees is thought to reflect HTLV-I evolution and the migrations of virally infected populations in the recent or distant past. Furthermore, there was a nearly perfect concordance between the clustering based on the LTR sequence homologies and the LTR RFLP subtypes suggesting that this rapid and simple technique is well suited to the investigation of HTLV-I molecular epidemiology. These results allow a new phylogenetic classification of HTLV-I genotypes into five major molecular subtypes:Cosmopolitan (C) subtype widespread all over the world, Japanese (J) subtype, West African (WA) subtype, Central African (CA) subtype and Melanesian (M) subtype.

Bovine leukemia virus can be classified into seven genotypes: evidence for the existence of two novel clades

“…2, Supplementary Figs S3-S5, Tables 2 and 3). Furthermore, the occurrence of long-distance dispersal achieved by a minority fraction of the virus population also supports the concept of viral transmission via close contact among individuals, which has been argued as an explanation for the characteristics of viral dispersion and endemic patterns in the related virus, HTLV (Cassar et al, 2007;Dube et al, 1993;Eirin et al, 2008;Vidal et al, 1994). As suggested previously (Camargos et al, 2007;Zhao & Buehring, 2007), the late strains dispersal caused by modern cattle trading may account for the current presence of more than a single group of viruses in certain geographical areas.…”

“…Likewise, correlations between genetic clustering and the geographical origin of particular viruses have been demonstrated for STLV (Makuwa et al, 2004) and HTLV (Cassar et al, 2007;Dube et al, 1993;Eirin et al, 2008;Vidal et al, 1994). For these viruses, it is also believed that this correlation is due to the migratory flow of their hosts (Cassar et al, 2007;Dube et al, 1993;Makuwa et al, 2004;Vidal et al, 1994). Therefore, a very plausible explanation that may account for the radiation of BLV genotypes could be that the diversification of the virus has been driven by the historical dispersion of its host, as the worldwide cattle population is closely linked to human colonization, ethnic history and animal domestication over the last 200-1000 years.…”

“…For instance, there is a strong dependence between the geographical origin and the genotype of Kaposi's sarcoma-associated herpesvirus (KSHV) isolates that has been attributed to the expansion of the distinct KSHV-infected populations following the major human migrations out of Africa and to the rest of the world (Hayward & Zong, 2007;Zong et al, 1999). Likewise, correlations between genetic clustering and the geographical origin of particular viruses have been demonstrated for STLV (Makuwa et al, 2004) and HTLV (Cassar et al, 2007;Dube et al, 1993;Eirin et al, 2008;Vidal et al, 1994). For these viruses, it is also believed that this correlation is due to the migratory flow of their hosts (Cassar et al, 2007;Dube et al, 1993;Makuwa et al, 2004;Vidal et al, 1994).…”

HTLV-1 Myelopathy in Kuwait: A Report of 2 Patients and Review of Possible Links

“…Five more Muslim Mashhadis have been reported by Vidal et al [19], A total of 11 HTLV-1-positive cases were reported from Egypt between 1984 and 1992. Only 1 suffered from myelopathy [20][21][22],…”

Reconstrucción de la evolución molecular de la infección actual por el virus linfotrópico humano tipo I en Colombia.

“…Con base en el análisis de polimorfismos en los tamaños de fragmentos de restricción (RFLP) (26) y de secuenciación de nucleótidos de las secuencias de las terminaciones repetidas largas del ADN proviral (LTR) (27), Vidal-Ureta et al (28) propusieron una clasificación del HTLV-I en subtipos geográficos y moleculares: el subtipo I que circula en África occidental y Zaire, el subtipo II o cosmopolita de amplia distribución a nivel mundial, el subtipo III o japonés, el subtipo melané-sico y el subtipo circulante en África central; además, estos análisis aportaron evidencias con relación con la estabilidad genética del HTLV-I.…”