Development of an enzyme immunoassay for the detection of Clostridium novyi type B alpha toxin

Clostridium novyi type B alpha toxin was purified to homogeneity and shown to have a molecular weight of 200 kD by SDS polyacrylamide gel electrophoresis. The toxin was toxoided and used to produce a pair of non-interfering monoclonal antibodies. Their specificity was confirmed by immunoblotting and bioassay. The monoclonal antibodies were used to develop an enzyme immunoassay which was more sensitive than bioassay, and permitted less than 1 ng/ml toxin to be detected in a rapid 10 min assay format. Use of the assay can eliminate the requirement for in vivo testing of novyi toxin and toxoid, provided measurements of biological activity are not required. Because of its speed and sensitivity, the assay can be used to monitor toxin production during fermentation and as an alternative to bioassay to measure antigen content during toxoiding and vaccine formulation.