Overgrowth of Clostridium perfringens clones with production of one or more of its toxin(s) results in diverse digestive and systemic pathologies in human and animals, such as cattle enterotoxaemia. The so-called beta2 toxin (CPB2) is the most recently described major toxin produced by C perfringens. In this study, the cpb2 ORF (cpb2FM) from a cattle C perfringens-associated enterotoxaemia was cloned and sequenced. The cpb2FM and its deduced nucleotide sequence clearly corresponded to the epb2 allele considered as "consensus" and not to "atypical" allele, despite its "non-porcine" origin. Expression assays of the recombinant toxin CPB2FM were performed in Escherichia coli and Bacillus subtilis with the expression vector pBLTS72, and by genomic integration by double recombination in B. subtilis. Highest level of production was obtained with the expression vector in B. subtilis 168 strain. The recombinant CPB2FM protein was purified and a specific rabbit polyclonal antiserum was produced. Polyclonal antibodies could detect CPB2 production in supernatants of C. perfringens from enterotoxaemic cattle. (C) 2007 Elsevier Inc. All rights reserved.