Development of process for the conjugation of capsular polysaccharide Haemophilus influenzae type b with tetanus toxoid.
Haemophilus influenzae type b (Hib) is an important encapsulated bacteria, which causes pneumonia, meningitis and septicaemia in infants. Prevention against infection is achieved by the currently available polysaccharide protein conjugate vaccine. However, due to its high production costs (around U$ 2,7 per dose) this formulation cannot be used in mass immunization programs in Brazil. In the present study, we developed a new method for the conjugation of Hib polysaccharide (PRP) and tetanus toxoid (TT). The hydrazone method is based on 3 singles steps: PRP oxidation, PRP derivatization with linker spacer and conjugation with TT in the presence of carbodiimide and an amino reactive ester. After detailed study of each step of method, the new process showed very good yield of conjugation even when it was scaled-up. The immunogenicity and the avidity index of hydrazone conjugate were evaluated and the results were comparable with those obtained with the commercial vaccine Hiberix®. The HPLC hydrazone profile was very similar to HPLC Hiberix profile. Finally, the new conjugation process allows the development of a powerful vaccine technology, constituting an excellent choice for the brazilian government.
Advisor:Martha Massako Tanizaki; Viviane Fongaro Botosso; Iolanda Midea Cuccovia; Maria Teresa Machini de Miranda; Adalberto Pessoa Junior; Martha Massako Tanizaki
School:Universidade de São Paulo
Source Type:Master's Thesis
Keywords: Capsular polysaccharide
Date of Publication:02/18/2008