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DNA sequences encoding the surface envelope glycoproteins of human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) were amplified by PCR from uncultured peripheral blood mononuclear cells obtained from patients with serologically defined HIV-1/HIV-2 mixed infections from Bombay, India. HIV-1-specific PCR products were obtained in seven of seven randomly chosen doubly reactive cases, while HIV-2-specific sequences were detected in five of seven cases (71%). DNA sequence analysis showed that the HIV-1 gp120 coding sequences were closely related to each other (nucleotide sequence divergence of between 3.1 and 6.8%). Phylogenetic tree analysis placed the Indian strains within the C subtype of HIV-1, being most similar to sequences previously found in East and South Africa. The HIV-2 sequences were also closely related to each other, with an overall sequence divergence of between 5.6 and 10.5%. The low level of nucleotide divergence among Indian HIV-1 and HIV-2 sequences suggests a fairly recent introduction of each virus into this population from a single point of entry in each case. The HIV-2 sequences reported here represent the first analysis of Asian HIV-2 strains and confirm the serological pattern previously detected in India. These data show that a substantial spread of HIV-2, together with HIV-1, has appeared outside Africa in a population hitherto unexposed to HIV. These findings imply that further spread of HIV-2 worldwide is to be expected and have important implications for future vaccine and therapy development.

Original publication




Journal article


Journal of virology

Publication Date





2161 - 2168


Georg-Speyer-Haus, Chemotherapeutisches Forschungsinstitut, Frankfurt, Germany.


Leukocytes, Mononuclear, Humans, HIV-1, HIV-2, Acquired Immunodeficiency Syndrome, HIV Seropositivity, HIV Envelope Protein gp120, Polymerase Chain Reaction, Sequence Analysis, DNA, Phylogeny, Amino Acid Sequence, Base Sequence, Consensus Sequence, Sequence Homology, Amino Acid, Molecular Sequence Data, India