Streptococcus pneumoniae Capsular Polysaccharide-Protein Conjugates (PCV)

Streptococcus pneumoniae capsular polysaccharide-protein conjugates are the active components in pneumococcal conjugate vaccines (PCVs). These molecules consist of purified capsular polysaccharides from specific S. pneumoniae serotypes that are chemically linked (conjugated) to a highly immunogenic carrier protein, most commonly CRM197, a non-toxic variant of diphtheria toxin. The primary function of these conjugates is to induce an immune response against the polysaccharide capsule of S. pneumoniae, which is its main virulence factor and helps it evade host immune clearance. When administered as a vaccine, the conjugated structure allows for recognition by both B cells (which recognize the polysaccharide) and T helper cells (which recognize peptides from the carrier protein after processing), leading to robust germinal center formation in lymph nodes.

Other names

Pneumococcal Conjugate VaccinePCV13PCV15PCV20PCV21

Induces a T-cell dependent immune response against Streptococcus pneumoniae capsular polysaccharides, leading to opsonizing antibody production and long-lasting immunity.