The Development Of Bivalent Toxoid Vaccine And Antisera Of Clostridium Perfringens Type C And D

Clostridium perfringens, a resident in the intestines of various animals, widely exist in the field. It is a pathogenic agent which acutely causes infectious disease of human and various kinds of animals. Short period of morbidity leads to quick death, resulting in heavy loss for farming industry. Necrotic enteritis and enterotoxemia can be induced only by Clostridium perfringens type C or D or co-infected with each other. But it is difficult to make the differentiation of type C and D in a short time of infection. In order to control the diseases caused by Clostridium perfringens, we developed the bivalent toxoid vaccine and antisera of Clostridium perfringens type C and D.The bacterial resistance is increasing with the widespread use of antibiotics. The diseases of clostridium perfringens are hard to be cured, however, the vaccine inoculation is the best way to prevent the diseases. On the basis of that exotoxin is the causative agent of the pathogenicity, a safe and effective vaccine was researched and developed. Generally, because of the positive correlation between vaccine efficacy and the concentration of antigen, the conditions of toxin production were optimized. Clostridium perfringens type C and D were inoculated in the same medium(4:3), and the exotoxins were produced prolifically. Median lethal dose of the exotoxin in mice is 2-5.8/mL. The toxoid vaccines respectively white oil as an adjuvant and aluminum hydroxide were prepared.Nowadays, in China, Clostridium perfringens vaccine is inactivated by aluminum hydroxide which can not fully protect the vaccinated animals, therefore, a safe and effective vaccine was studied and developed. In order to demostrate the safety and efficacy of the vaccine, rabbits were immunized in large doses of both kinds of vaccines. Minimal lethal dose of the exotoxin in rabbits was measured. Challenge protection test was conducted 21 days after rabbits immunized with various doses. The results showed that there was no ulcer and granulomas at injection site and the absorption of the two vaccines was fine. The minimumlethal dose of type C is 0.04 m L in rabbit, while the minimum lethal dose of type D is 0.4 mL.Both vaccines were safe. For rabbit, the minimum immune dose of aluminum hydroxide vaccine was 2 ml, while the white oil toxoid vaccine was 1m L.The diseases caused by Clostridium perfringens is difficult to be cured with antibiotics.The antisera as specific therapeutic agents could neutralize toxins swiftly. The toxoid vaccine with high concentration of antigens(1stimmunogen) and sterilization exotoxins(2nd immunogen) were used to prepare the antisera with high titers. Indirect ELISA was used to monitor the the antibody development. The results showed that 0.1 mL antiserum can neutralize 400 units MLD of type C and 600 units MLD of type D in mice. There will be a prosperous future for the anisera application.