Detection of neutralizing antibodies against alpha-toxin of different Clostridium septicum strains in cell culture

Clostridium septicum, a ubiquitous organism, is the pathogen which causes t he classical malignant edema after injuries. Because of its strong cytotoxi c alpha-toxin, infections are often lethal. To prevent losses in animals, v accination with alpha-toxoid vaccines is carried out. Quality control of th e vaccines is done by a neutralization test in mice. A cytotoxin lest and a s an alternative method to detect neutralizing antibodies, a cytotoxin inhi bition test was standardized. In the studies, alpha-toxin of the C. septicu m reference strain (NC 547) from the National Collection of Type Cultures w as compared with alpha-toxin of a field strain from an outbreak in Germany. Sera from five heterologous polyvalent and three monovalent vaccines from eight rabbit groups were available. Each vaccination had been carried out a ccording to the procedure of the German Pharmacopoeia. In three out of the five sera of the groups vaccinated with the heterologous polyvalent vaccine , cytotoxin neutralizing antibodies were detected. High antibody titers wer e observed in sera of rabbits vaccinated with a Vaccine of strain NC 547, l ower titers in the sera of rabbits vaccinated with a vaccine of the field s train. No cytotoxin neutralizing antibodies could be found in the sera of r abbits vaccinated with the monovalent C. chauvoei vaccine. The toxins of al l strains showed the same ranking of the vaccines. Vaccines which caused hi gh antibody titers in the animals were detected by all toxins as such, as w ell as vaccines which had medium or low antibody inducing capacity. The res ults were independent of the C. septicum strain used for the production of alpha-toxin. (C) 1999 Federation of European Microbiological Societies. Pub lished by Elsevier Science B.V. All rights reserved.