Group B streptococcal infections are a leading cause of neonatal sepsis. The incidence of invasive infections during the first two months of life is approximately 2-3 cases per 1000 live births. Despite advances in diagnosis, supportive care and treatment, mortality and morbidity from these infections continue to be substantial. Of the four capsular types, type III strains account for about two thirds of the isolates associated with invasive neonatal infections. It is established in the literature that human immunity to group B streptococci-correlates with type-specific anticapsular antibodies. Bacterial capsular polysaccharides (CPS), in general, are poor and are T-cell independent immunogens. In many cases, the poor immunogenicity of these CPS was improved by the production of conjugated vaccines. Covalently binding CPS to carrier proteins made them better immunogens as evidenced by their eliciting higher antibody levels, and T-cell dependent immune response. Preliminary results showed that types III, 11 Ia, and lb CPS are relatively poor inununogens when administered to normal healthy adult human volunteers. This research is for the purification of type III CPS and the preparation of different conjugates with different carrier proteins. Each conjugate will be chemically, physically and immunologically characterized. Optimal conditions for the production of the vaccines will be established. Moreover, the biological activity of the antibodies elicited by the conjugated vaccines will be evaluated in an in-vitro opsonophagocytosis assays.Awardee's statement of the potential commercial applications of the research:Our ultimate goal is to develop a conjugated vaccine containing purified CPS from each of the group B streptococcus capsular types for evaluation in humans as active vaccines, and for antibody stimulation in plasma donors for passive immunization use.National Institute of Allergy and Infectious Diseases (NIAID)
