SPECIFICITY OF THE IMMUNE-RESPONSE TO HAEMOPHILUS-DUCREYI

The specificity of the antibody response to Haemophilus ducreyi in ser a from patients attending a sexually transmitted disease clinic in Sou th Africa has been studied using immunoblotting. Patients with chancro id were shown to have higher levels of IgG (mean 0.74, SD 0.34) to H. ducreyi than those with no history of chancroid (mean 0.34, SD 0.19). The pattern of the antibody specificity was highly variable between pa tients with culture proven chancroid but there was no observed strain specificity. In comparison, the patterns obtained using sera from pati ents without known exposure to H. ducreyi showed less Variation betwee n patients and were of less intensity at the dilution used. Sera from patients with chancroid recognised epitopes on proteins that varied in molecular weight between strains, particularly of 60-66 kDa (10 of 36 patients) and 25-27 kDa (8 of 36 patients). In addition epitopes were recognised on the GroEL and/or DnaK heat shock proteins in 13 of 36 s era tested. There was no apparent change in the epitopes recognised on proteins between the homologous and heterologous strains. Patterns of antibody specificity in sequential sera only varied in one of six pat ients tested. (C) 1995 Academic Press Limited