Peptide based enzyme-linked immunoassays for detection of anti-HSV-2 IgG in human sera

Glycoprotein G of HSV-2 (gG2) and a peptide, corresponding to a previously recognised immunodominant epitope spanning residues 561-578 of the protein, were compared directly for type-specific serodiagnosis of HSV-2. The protein was affinity purified and obtained in a commercially available EIA kit while the peptide, previously designated as peptide 55, was made as a multiple antigenic peptide. A panel of 100 characterised serum samples (60 HSV-2 positive, 20 HSV-1 positive and 20 HSV negative) was screened using the two antigens. The intact protein and peptide 55 showed the same sensitivity for antibodies in the serum of HSV-2 infected individuals, reacting with 96.7% (58/60) of the samples. The peptide did not react with any of the HSV-1 positive or HSV negative sera. In contrast, gG2 gave a number of false positive results, reacting with 20% (4/20) of the HSV-1 positive sera and 10% (2/20) of the HSV negative sera. The superior performance of peptide 55, together with the very much lower costs of its production, compared with gG2 suggest that the peptide will become the antigen of choice in enzyme immunoassays for type-specific serodiagnosis of HSV-2.