Antigen detection and immunological typing of Haemophilus ducreyi with a specific rabbit polyclonal serum.
A rabbit polyclonal serum was raised against the 29-kDa species-specific marker, as well as the 30- to 34-kDa immunotype-specific markers of Haemophilus ducreyi described elsewhere (E. Roggen, S. De Breucker, E. Van Dyck, and P. Piot, Infect. Immun. 60:590-595, 1992). These antigens were purified from a cocktail of H. ducreyi isolates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The immune serum reacted in enzyme-linked immunosorbent assay (ELISA) preferentially with H. ducreyi, at a titer as high as 50,000. To make it specific to H. ducreyi, nonspecific antibodies were removed by adsorption on a mixture of Haemophilus spp., Escherichia coli, Candida albicans, and Corynebacterium spp. In the 29- to 34-kDa region of immunoblot profiles from H. ducreyi isolates (n = 450), the adsorbed serum revealed essentially the same antigens as did a pool of well-characterized human sera. Yet, eight different immunotypes were observed. With this rabbit polyclonal serum, an ELISA-based antigen detection test was developed. The adsorbed serum reacted specifically with all H. ducreyi isolates tested (n = 450), but not with other bacterial species (n = 15). This test was evaluated with a limited number of clinical specimens from African patients with culture-proven chancroid and no evidence for any other ulcerating etiology (n = 10) and a number of chancroid-negative control patients from Belgium (n = 20). Within this context, the test yielded a sensitivity and specificity of 100%.
Roggen
E L
EL
Department of Infection and Immunity, Institute of Tropical Medicine, Antwerp, Belgium.
Pansaerts
R
R
Van Dyck
E
E
Piot
P
P
D000818:Animals; D000907:Antibodies, Bacterial; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000302:isolation & purification*; D001431:Bacteriological Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D006191:Haemophilus ducreyi / Q000145:classification* / Q000276:immunology*; D006801:Humans; D011817:Rabbits; D012703:Serotyping
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial