ABSTRACT
OBJECTIVES: The aim of our investigation was to study the HIV-1 env V3 loop sequences of the subtype A variant of the virus actively circulating in the territory of Eastern Europe (A1-EE). DESIGN: It appears that the characteristics of HIV-1 V3 loop sequences of the thoroughly studied subtype B strains determine the viruses tropism and phenotype. We were interested to find out to what extent these trends are preserved with the subtype A isolates spread in Eastern Europe. METHODS: About 474 HIV-1 strains were isolated by cocultivation with phytohemagglutinin stimulated and interleukin-2 activated PBMC. Isolates were subtyped after distinct regions gag, pol and env were amplified by nested polymerase chain reaction. V3 sequences were studied in detail and compared with the isolates that appeared as SI or NSI in test-cultures MT-2. RESULTS: The subtype A HIV-1 strains spread in Eastern Europe appeared to have V3 loop sequences with a high level of conservatism. The consensus sequences of the SI and NSI isolates proved identical, and correspond to the phenotype markers of subtype B NSI strains. Nevertheless, the subtype A SI isolates induced active syncytium-formation processes in the MT-2 test culture. CONCLUSION: The data obtained evidenced to the following: the HIV-1 subtype A variant spread in Eastern Europe, is capable of using for interaction with receptor structures of sensitive cells the tools and mechanisms, which are significantly different from those described for subtype B.
