Study On Improving The Immunogenicity Of Tetanus Toxoid

Tetanus toxoid (TT) consists of a formaldehyde-treated tetanus toxin is produced by Clostridium tetanus under anaerobic conditions, and does not have the toxicity, but still contains the antigenicity. After refined, it can be used as vaccine for tetanus prophylaxis. The disease itself does not induce immunity. Therefore, prophylaxis against tetanus is usually conducted by frequent boosters throughout the life of human and animals. To relieve side-effects, boost the result of immunization, reduce injection times, raise the coverage area of immunity against the toxin, the experiment used the prokaryocyte vector to express the C fragment of tetanus toxin which has high immunogenicity. The recombinant C fragment of tetanus toxin (rTTC) was expressed to produce vaccine and used to immunize human and animals in order to avoid severe adverse reactions. In the other hand, the difunctionality cross-linking agent polymerized toxin can conjugate toxin to polymeride between toxin molecules. The polymeride toxoid has many epitopes and large molecular weight, and can be used as antigen to stimulate high antibody level and protect the human and animals to avoid tetanus toxin attack.The fragment C gene of tetanus toxin was amplified from Clostridium tetani genomic DNA by PCR. It was inserted into the high-expression vector pET32a, and expression of this plasmid in Escherichia coli BL21 (DE3) resulted in the production of a fusion protein. The expression was induced by IPTG and the fusion protein expression was observed under different conditions. The fusion protein was purified significantly in one step by affinity chromatography then used to immunize mice, and the antibody titers were tested. The result of SDS-PAGE showed that a specific recombinant protein was expressed and accounted for 28.19% of the soluble protein. The final purity was 96.92%. After the third immunization 14 days, the anti-tetanus antibody titers of the mice in rTTC group were detected. The recombinant protein is an immunogenic antigen of tetanus toxin and thus constructs a basis for the current vaccine in the future.The tetanus toxin were produced by cultured C. tetanus in a strict anaerobiosis condition, were removed the toxigenicity, and refined. During that time, qualification of toxigenicity...