Use of a conserved immunodominant epitope of HIV surface glycoprotein gp41 in the detection of early antibodies

An enzyme immunoassay (EIA) utilizing a synthetic peptide analogue of HIV gp41 (amino acids 579-599, RILAVERYLKDQQLLGIWGCS) as antigen was compared with two commercial assays (Genetic Systems, Abbott ENVACORE) for the ability to detect antibodies in the early stages of infection. Two panels, consisting of 96 sera from 15 people and 140 sera from 44 people seroconverting to HIV, were examined. In the first group the synthetic peptide assay (gp41 EIA) detected antibodies before the Genetic Systems EIA in seven out of 15 people and concurrently in the remaining eight. With the second panel the Abbott ENVACORE assay detected antibodies before the gp41 EIA in two out of 44 people while the gp41 EIA detected antibodies first in six out of 44. In the remaining 36 people antibodies were detected simultaneously by the two tests. The gp41 EIA usually detected anti-HIV antibodies before or concurrently with the two commercial assays examined suggesting that the epitope cluster represented by this peptide is recognized early in infection.