Isolation & preliminary characterization of two HIV-2 strains from Pune, India

Two HIV-2 strains were isolated from peripheral blood mononuclear cells of two HIV-2 seropositive patients with pulmonary tuberculosis by co-cultivating the cells with phytohaemagglutinin-P stimulated heterologous normal lymphocytes. Biological characterization of the isolates indicated that both isolates were syncytium inducing and induced cytopathic effect in the form of giant cells and syncytia formation in four T lymphoid cell lines. The isolates differed in their replication pattern. The isolates were confirmed as HIV-2 by nested PCR using HIV-1 and HIV-2 specific oligonucleotide primers from the env region and by supplementary tests like indirect immunofluorescence assay, syncytium inhibition assay using reference and HIV-2 reactive patients' sera, western blot and electron microscopy. Neutralization of one isolate (TB1) with two Senegal reference sera also indicated that the isolate may be related to the Senegal strain. To our knowledge, this is the first report of isolation of HIV-2 in India.