Carbohydrate-based vaccines of Streptococcus pneumoniae

Abstract:

Streptococcus pneumoniae causes a range of diseases such as invasive infections (bacteremia of septicemia and meningitis, etc.) and common mucosa infections (pneumonia, otitis media, sinusitis, etc.). According to the structure of surface capsular polysaccharide, it is classified into different serotypes (98 serotypes identified, with 20 highly virulent). A number of related vaccines have been developed, among which 23-valent pneumococcal polysaccharide vaccine (PPV23) and 13-valent pneumococcal protein-conjugate vaccine (PCV13) are commonly used. However, natural polysaccharide antigens face some challenges, such as difficulty in purification and uneven composition. Therefore, synthetic oligosaccharide-based glycoconjugate vaccines have become a promising alternative. After vaccination, serotype substitution occurs and the pathogenicity rate of certain serotypes (such as serotype 3 and 19A) increases. Thus, serum-independent protein vaccines and whole-cell vaccines have become a new research focus. This review took S. pneumoniae serotype 3 vaccine as an example to summarize the mechanism of different types of vaccines and their research progress.