The production and characterisation of rabbit antiserum and murine monoclonal antibodies to Haemophilus ducreyi.

Rabbit antiserum and murine monoclonal antibodies were raised against a strain of Haemophilus ducreyi. The antiserum gave high immunofluorescence titres and strong dot blot reactions with all H. ducreyi strains tested and the only cross reaction was with Bordetella pertussis. Three monoclonal antibodies, all of isotype IgG2a, also gave high immunofluorescence titres with H. ducreyi but did not cross react with any other species tested. Immunoblotting showed the monoclonal antibodies to react with a single polypeptide band of mol. wt 29,000 in the outer-membrane fraction of H. ducreyi. These antibodies have potential for use as diagnostic reagents and for investigating the pathogenicity of H. ducreyi.

Rapid detection of Haemophilus ducreyi in clinical and experimental infections using monoclonal antibody: a preliminary evaluation.

A monoclonal antibody raised against Haemophilus ducreyi was tested for its sensitivity and specificity as an immunofluorescence (IF) reagent using simulated vaginal smears containing H. ducreyi, smears taken from skin lesions of mice infected with H. ducreyi and patients from South Africa, Thailand and Malaysia with clinically diagnosed chancroid. The IF test was more sensitive than culture or Gram staining in the simulated smears, theoretically detecting less than 4 organisms/sample. It detected H. ducreyi in 95% of the animal lesions compared with 14% detected by culture. Immunofluorescence testing identified over 90% of culture-positive cases of chancroid but also detected organisms in some culture-negative cases where clinical evidence for the diagnosis was strong. These results suggest that this antibody may provide a simple, rapid and sensitive means of detecting H. ducreyi in cases of chancroid.