Preparation and immunogenicity of a conjugate composed of pneumococcal type 18C capsular polysaccharide bound to tetanus toxoid

A conjugate of pneumococcal type 18C capsular polysaccharide(CPS) binding with tetanus toxoid (TT) was prepared by carbodiimide-mediated coupling of apidic acid hydrazide (ADH)derivative.The physico-chemical property, antigen specificity and immunogenicity of conjugate have been investigated. The results showed the CPS-TT can produce visible precipitation lines with antisera of pneumococcal 18C type polysaccharide and tetanus toxoid respectively.The ration of proteine and polysaccaride is 1.86,molecular size of conjugate is 0.058(Kd value),it can induce higher levels of specific serum lgG antibody responses in mice. Furthermore along with the increasing of injection doses, the antibody concentration are significantly rising(P=0.01) to show the boosed effection. In summary, the prepared pneumococcal conjugate showed satisfactory immugenicity in mice and maintained perfect antigenicity, it has the property of thymus dependent antigen.