title: 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.
abstract: 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.
authors.affiliation: Istituto di Genetica Biochimica ed Evoluzionistica del C.N.R., Pavia, Italy. marco.salemi@uz.kuleuven.ac.be
authors.forename: M
authors.initials: M
authors.lastname: Salemi
authors.forename: A M
authors.initials: AM
authors.lastname: Vandamme
authors.forename: F
authors.initials: F
authors.lastname: Guano
authors.forename: C
authors.initials: C
authors.lastname: Gradozzi
authors.forename: E
authors.initials: E
authors.lastname: Cattaneo
authors.forename: C
authors.initials: C
authors.lastname: Casoli
authors.forename: U
authors.initials: U
authors.lastname: Bertazzoni
mesh_terms: D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D005060:Europe / Q000453:epidemiology; D016679:Genome, Viral; D015491:HTLV-II Infections / Q000453:epidemiology* / Q000821:virology; D015367:Human T-lymphotropic virus 2 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D015819:Substance Abuse, Intravenous / Q000821:virology
chemical_list: D017931:DNA Primers