Oyston Petra C F, Payne Dean W, Havard Helen L, Williamson E Diane, Titball Richard W
Defence Evaluation and Research Agency, CBD Porton Down, Salisbury, Wiltshire SP4 0JQ, UK.
Microbiology (Reading). 1998 Feb;144 ( Pt 2):333-341. doi: 10.1099/00221287-144-2-333.
A panel of ten site-directed mutants of Clostridium perfringens epsilon-toxin was generated. All of the mutated proteins expressed in Escherichia coli were recognized in immunoblots by a neutralizing mAb raised against wild-type native epsilon-toxin. The cytotoxicity of the site-directed mutated toxins was assayed in vitro against MDCK cells. One mutation resulting in loss of activity in the assay was identified. This non-toxic protein was derived by substituting a proline for the histidine at residue 106 of the toxin. Immunization of mice with the non-toxic mutated epsilon-toxin resulted in the induction of a specific antibody response and immunized mice were protected against 1000 LD50 doses of wild-type recombinant epsilon-toxin.
