ISOLATION, SEQUENCING AND ULTRASTRUCTURE OF HTLV-I AND HTLV-II - PRESENCE OF THE HTLV-II SUBTYPE B AMONG SPANISH INTRAVENOUS DRUG-ADDICTS

Background: Six cases of HTLV-I/II infection were selected for isolati on and characterization of these retrovirus. Methods: Detection of ant i-HTLV antibodies was carried out by enzyme immunoassay (EIA), immunof luorescence (IFI), and Western blot (WB). Analysis of proviral DNA was performed by PCR. Viral culture and partial sequencing of the pol and pX genes were carried out. Electron microscopy morphologically charac terized the viral particles. Results: Serologic study demostrated four cases of HTLV-II, one of HTLV-I, and one non-typeable HTLV infections . This last case was confirmed as positive for HTLV-II by PCR. Five ne w HTLV-II and one HTLV-I infected cell lines have been established by co-culture. Electron microscopy allowed morphologic characterization o f the viral particles found in the infected cells. The sequence of the five strains of HTLV-II was identical demonstrating a divergence of 0 .49% in the pX region and of 4.5% in the pol region compared with the HTLV-II Mo prototype. Comparison of these sequences with those corresp onding to different strains of HTLV-II isolates from American Indians (subtypes b) suggest that these Spanish strains are more closely relat ed with the subtype b than with the subtype a (HTLV-II Mo). Genetic va riability study did not reveal any change in the sequence of these sta ins suggesting that the variability of these retroviruses is very infr equent in the regions studied. The analysis of the pol region of the H TLV-I strain demonstrated a divergence of 3.4% with respect to the seq uence of the ATK-1 prototype (Japan) and of 1.7% of the strain HS-35 ( Caribbean) showing a greater relation with the Caribbean strains than with those from Japan. Conclusions: The presence of HTLV-II subtype ha s been confirmed among intravenous drug addicts in Spain. Isolation an d characterization of the HTLV-I strain demonstrated that this also ci rculating around Spain despite its South American origin.