V3 SEQUENCES IN PRIMARY HIV-1 INFECTION

Objective: To determine HIV-1 genomic RNA and proviral DNA sequences o f the third hypervariable region (V3 loop) of the envelope protein in patients with primary HIV-1 infection (PHI), and to compare these sequ ences with sequences from patients with more advanced HIV-1 infection. Methods: Sera and peripheral blood mononuclear cells were collected f rom 24 patients with PHI living in Geneva. V3 sequences were determine d using direct solid-phase sequencing on polymerase chain reaction (PC R) products. Results: A 100% homology rate was observed between HIV-1 genomic RNA and proviral DNA paired nucleotide sequences from the V3 r egion in the 24 patients. Using a limiting dilution approach for three patients, a unique V3 sequence was observed for the genomic RNA. Thre e out of 24 amino-acid sequences presented the characteristic signatur e sequence QRGPGR, first described for the HIV-1(LAI) isolate, which i s associated with lymphocytotropism. These three isolates also present ed, for the V3 loop, a characteristic elevated charge (8) at physiolog ical pH in comparison with the other isolates (3-5). There was no sign ificant difference in the distribution of amino acids between the 24 V 3 loop sequences from patients with PHI and 245 V3 loop sequences of t he B subtype determined in patients with more advanced HIV-1 infection . Conclusion: The paired sequences recovered from HIV-1 genomic RNA an d proviral DNA are identical for each of the 24 patients with PHI. Thr ee isolates had the V3 loop characteristic signature sequence QRGPGR f irst described for the HIV-1(LAI) isolate. There is no characteristic V3 loop pattern associated with PHI isolates.