A note on a new method for preparing a potent anti-chauvoei vaccine

Blackleg: A Review of the Agent and Management of the Disease in Brazil

The genus Clostridium is an important group of pathogenic and nonpathogenic Gram-positive anaerobic bacteria with a sporulation capacity and wide distribution in different environments, including the gastrointestinal tracts of healthy and diseased animals and humans. Among the pathogenic species of the genus, Clostridium chauvoei stands out as a histotoxic agent. It causes significant myonecrosis such as blackleg, a disease with high lethality, especially in young cattle, and is responsible for significant livestock losses worldwide. The pathogenicity of the disease is complex and has not yet been fully elucidated. Current hypotheses cover processes from the initial absorption to the transport and deposition of the agent in the affected tissues. The virulence factors of C. chauvoei have been divided into somatic and flagellar antigens and soluble antigens/toxins, which are the main antigens used in vaccines against blackleg in Brazil and worldwide. This review provides important information on the first and current approaches to the agent C. chauvoei and its virulence factors as well as a compilation of data on Brazilian studies related to blackleg.

Production of toxic antigens in dialyzed cultures of microorganisms

Data on the production of clostridial toxins in dialyzed cultures are summarized. Principal modifications of this cultivation technique suitable for both research and production are shown. If toxins are released from the cells by autolysis (neurotoxins of Clostridium tetani, C. botulinum; lethal factors of C. novyi and C. sordellii), a 10-fold increase of the antigen concentration in filtrates of dialyzed cultures is found in comparison with normal cultures. If toxins are excreted already during growth (lethal factors of C. perfringens type A, C. septicum), the positive effect of the technique is less significant. A dialyzed culture ensures a well-balanced production of toxic filtrates that contain highly concentrated, relatively pure and strongly immunogenic antigens.

Dialysis culture of microorganisms: design, theory, and results

Images