Analysis of immunogenic epitopes in choline binding protein of Streptococcus pneumoniae serotype 19F

Streptococcus pneumoniae (pneumococcus) is an important pathogen that causes significant annual mortality in children less than 5 years worldwide. S. pneumoniae serotype 19F is a major cause of pneumococcal disease in children globally. Pneumococcal capsule is the antigen used in the construction of pneumococcal vaccines. However, due to its weak immunogenicity in children, it is coupled chemically to an immunogenic carrier protein. The high manufacturing cost of these vaccines encouraged the development of proteinaceous vaccines against pneumococci. Cell surface proteins are key factors in the infection process of pathogenic bacteria and are attractive as antigens for the vaccine development. Our previous study showed that choline binding protein (CBP) of serotype 19F pneumococcus, is an antigenic cell surface protein and it is not able to induce autoimmunity. Regarding the importance of inducing both antibody and cellular immune responses for protection against pneumococcus, in this study, we aim to determine the presence of immunogenic B- and T-cell epitopes in CBP to evaluate its suitability as a vaccine candidate against serotype 19F pneumococcus.