Serotype analysis of Indian patients with HIV infection

In India laboratory researchers used a solid-phase method on an applied biosystem model 431-A synthesizer to synthesize five peptides of the V3 loop of HIV-1 ranging from 25 to 35 amino acids in length designated as Mn EL NOF Indian and IIIB. These peptides represented serotypes prevalent in different parts of the world. One of the researchers had earlier derived the Indian consensus from 13 isolates from the Punjab. The researchers conducted systematic serotyping of 100 HIV-1 positive samples using the five peptides. 56 patients were in stage I HIV-1 infection 18 in stage II and 26 in stages III or IV. ELISA patterns were highly concordant with a positivity rate of 82% for the NOF peptide and 79% for the Indian peptide. In fact 90% of all samples reacted to NOF or Indian peptides even though these patients were from different areas of the world (Uganda Congo US Persian Gulf Europe and Thailand). This finding suggests that heterosexual spread of HIV-1 has tended to take place among communities outside India and not across Indian communities. 21% of all samples reacted to IIIB. All reactions except one appeared to have some cross-reactivity of NOF Indian and IIIB. Nine patients did not respond to any of the five peptides. These findings show that 82% of all patients had an HIV-1 strain (i.e. NOF peptide) related to the South African type. They contribute to the design of relevant vaccine strategies and may have forensic implications for tracing the source of an HIV-1 infection. The findings also indicate a need to incorporate envelope sequences of peptides relevant to a geographic area to minimize false-negative reactions.