HUMORAL IMMUNE-RESPONSE OF HUMANS TO LIPOOLIGOSACCHARIDE AND OUTER-MEMBRANE PROTEINS OF HAEMOPHILUS-DUCREYI

The humoral immune response to purified lipooligosaccharide (LOS) and outer membrane proteins (OMP) of Haemophilus ducreyi was evaluated. Sera from chancroid-endemic (Uganda, Kenya) and -nonendemic (Canada) countries were tested by an ELISA. The response to OMPs was cross-reactive with other Haemophilus species, and elevated levels of antibody were detected in patients that did not have chancroid. The LOS component stimulated an H. ducreyi-specific immune response that was detected only in patients with chancroid. The sensitivity of the LOS ELISA was 96% (95% confidence interval, 89.9%-100%) and the specificity was 97% (95% confidence interval, 95.8%-98.2%). Thus, the anti-H. ducreyi LOS immune response is a significant diagnostic and epidemiologic indicator.