Anti-C. diphtheriae Toxin Monoclonal antibody, Clone EjE2

Introduction: Potentially toxigenic Corynebacteria (Corynebacterium diphtheriae, Corynebacterium ukerans, and Corynebacterium pseudotuberculosis) can produce diphtheria toxin and stated as diphtheria causative agent. The bacteria causing diphtheria could be identified by Cystinase test on the Tinsdale medium, while its toxigenicity determined by Elek test on the Elek medium. This study aims to develop a new modified medium for both Cystinase and Elek tests simultaneously. Methods: There were ten reference strains of bacteria used for the modified medium optimization. Moreover, 15 clinical isolates were used as samples in the modified medium testing. The result of Cystinase and Elek tests on the modified medium was compared with the standardized tests on the Tinsdale and Elek mediums. Results: Twelve of 25 isolates tested on the modified medium were identified as toxigenic strain, corresponding with the result from standardized Elek test on the Elek medium. Moreover, 16 of 25 isolates tested on the modified medium were identified as positive for Cystinase test. The similar result was obtained using the standardized Cystinase test on the Tinsdale medium. This result was visible 24 hours after incubation. The modified medium was in excellent condition with the consistent result after stored in half-finished condition for 32 days at 2-8 degrees C. Conclusion: The modified medium developed in this study was a new good medium that could be used for Cystinase and toxigenicity tests simultaneously.

Diphtheria toxin is one of the best investigated bacterial toxins and the major virulence factor of toxigenic Corynebacterium diphtheriae and Corynebacterium ulcerans strains. However, also diphtheria toxin-free strains of these two species can cause severe infections in animals and humans, indicating the presence of additional virulence factors. In this study, we present a first characterization of two proteins with cytotoxic effect in corynebacteria. A putative ribosome-binding protein (AEG80717, CULC809_00177), first annotated in a genome sequencing project of C. ulcerans strain 809, was investigated in detail together with a homologous protein identified in C. diphtheriae strain HC04 (AEX80148, CDHC04_0155) in this study. The corresponding proteins show striking structural similarity to Shiga-like toxins. Interaction of wild-type, mutant and complementation as well as overexpression strains with invertebrate model systems and cell lines were investigated. Depending on the presence of the corresponding genes, detrimental effects were observed in vivo in two invertebrate model systems, Caenorhabditis elegans and Galleria mellonella, and on various animal and human epithelial and macrophage cell lines in vitro. Taken together, our results support the idea that pathogenicity of corynebacteria is a multifactorial process and that new virulence factors may influence the outcome of potentially fatal corynebacterial infections.