Complete nucleotide sequence of the Italian human T-cell lymphotropic virus type II isolate Gu and phylogenetic identification of a possible origin of South European epidemics

• Published in: Journal of general virology 1996-06, Vol.77 (6), p.1193-1201
• Main Authors: Salemi, Marco, Vandamme, Anne-Mieke, Guano, Fulvio, Gradozzi, Chiara, Cattaneo, Ercole, Casoli, Claudio, Bertazzoni, Umberto
• Format: Article
• Language: English
• Subjects: Base Sequence; Cells, Cultured; DNA Primers; Europe - epidemiology; Genome, Viral; HTLV-II Infections - epidemiology; HTLV-II Infections - virology; Human T-lymphotropic virus 2 - classification; Human T-lymphotropic virus 2 - genetics; Human T-lymphotropic virus 2 - isolation & purification; Humans; Italy - epidemiology; Molecular Sequence Data; Phylogeny; Polymerase Chain Reaction; Substance Abuse, Intravenous - virology
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-77-6-1193

1 Istituto di Genetica Biochimica ed Evoluzionistica del C.N.R., via Abbiategrasso 207, I-27100 Pavia, Italy 2 Rega Institute and University Hospital, Leuven, Belgium 3 IRCCS Policlinico S. Matteo, Pavia, Italy 4 Istituto Patologia Medica, Parma, Italy and 5 Istituto Biologia e Genetica, Università di Verona, Italy The complete nucleotide sequence of a human T-cell lymphotropic virus type II isolate (HTLV-II-Gu) from an Italian injecting drug user was obtained, representing the first entire sequence of a European HTLV-II isolate. The HTLV-II-Gu genome was more similar to the HTLV-IIb-NRA isolate (98.4%) and HTLV-IIb-G12 (98.2%) than to HTLV-IIa-Mo (95.2%). The classification of HTLV-II-Gu as subtype IIb was confirmed by restriction analysis. Just as for HTLV-IIa strain Mo, HTLV-IIb-Gu cultured lymphocytes produce two additional mRNAs generated through alternative splicing in the pX region. A phylogenetic analysis was performed by using the methods of neighbour-joining and parsimony with bootstrapping, and maximum likelihood. The different gene regions were analysed separately, comparing Gu with all other HTLV-II strains presently available. In the LTR, as well as in other genome regions, a clear separation between IIa and IIb was evident, and within the IIb subtype three clusters were present of which two were well supported; one contained exclusively Amerindian strains and the other included all Italian and Spanish strains together with two strains obtained from New York drug users. All data clearly showed that HTLV-IIa and IIb subtypes are closely related and are equidistant from HTLV-I, suggesting that both groups evolved simultaneously. The results suggest that HTLV-II-Gu and other IIb South European isolates were probably derived from North American IIb isolates. The data also indicate that sequence analysis is necessary to further classify IIa and IIb subtypes. * Author for correspondence. Current address: Rega Institute, Minderbroedersstraat 10, B-3000 Leuven, Belgium. Fax [phone], e-mail [e-mail] Received 10 October 1995; accepted 13 February 1996.