Evidence for the HTLV-IIa and HTLV-IIb subtypes in Southern Europe.
Int Conf AIDS 1996 Jul 7-12; 11:220 (abstract no. Tu.A.165) Vallejo A, Ferrante P, Soriano V, Calabro ML, Mancuso M, Heredia A, Mannella E, Garcia-Saiz A, Gonzalez-Lahoz J, Hewlett IK; FDA/CBER, Rockville, MD, USA.
Human T-cell lymphotropic virus type II (HTLV-II) has been subtyped into two major groups, IIa and IIb, according to molecular studies involving env gene sequencing. Subsequently, this retrovirus was further subclassified by examining the long terminal repeat (LTR), the most divergent genomic region. Sequence analysis and restriction fragment length polymorphism (RFLP) applied to the LTR region identified either four or five groups within the IIa subtype (depending on the restriction enzyme sets used) and six within the IIb subtype. In this study, we analyzed the LTR sequences of 29 samples obtained from HTLV-II-infected individuals living in Spain and Italy, which included 24 injecting drug users (IDUs), 3 blood donors and 2 subjects at risk for HIV/HTLV infection. Sequence analysis and phylogenetic analysis of 720 bp of the LTR performed in 10 Spanish samples showed that all these samples belonged to IIb subtype with a divergence of 7.5% and 1.66% compared to MoT (IIa) and NRA/G12 (IIb) isolates, respectively. RFLP analysis demonstrated the presence of the IIb4 subtype restriction pattern in 26 samples, a IIb5 subtype pattern in one Italian injecting drug user, and a IIa0 subtype pattern in 2 Italian samples (blood donors), according to Switzer's nomenclature (Switzer WM, et al. J Virol 1995;69:621-632). This is the first report of the presence of IIb5 in Southern Europe and IIa0 among Italian blood donors. RFLP correlated with nucleotide sequence and phylogenetic data obtained in this study, demonstrating the ability of the RFLP method to predict the phylogroup of HTLV-II-infected samples.
Keywords: AEGIS, Human T-lymphotropic virus 2, Europe, Polymorphism, Restriction Fragment Length, Deltaretrovirus Infections, Terminal Repeat Sequences, Italy, Blood Donors, Genes, env, Spain, Sequence Analysis, Human, genetics, ICA11
