Streptococcus pneumoniae surface antigen

Streptococcus pneumoniae surface antigens, which include both the complex capsular polysaccharides and various surface-anchored proteins, are the primary determinants of the bacterium's pathogenicity and the central targets for immunization strategies. The polysaccharide capsule is the most critical virulence factor, providing a physical barrier that prevents opsonization and subsequent phagocytosis by host immune cells; there are currently over 100 recognized serotypes based on capsule structure [1]. Surface proteins, such as Pneumococcal surface protein A (PspA) and Pneumococcal surface protein C (PspC), further contribute to virulence by facilitating adherence to the respiratory epithelium and inhibiting the host's complement system [2]. Current therapeutic interventions primarily involve conjugate and polysaccharide vaccines designed to elicit a robust humoral immune response against specific capsular serotypes [3]. While these vaccines have significantly reduced the burden of invasive pneumococcal disease, the high degree of antigenic variation remains a challenge, leading to the phenomenon of serotype replacement and driving research into protein-based vaccines that could offer broader, serotype-independent protection [4].

Other names

Pneumococcal surface antigensPneumococcal capsular polysaccharidesPneumococcal surface proteinsCPSPspAPspCCbpA

Vaccine-induced production of opsonizing antibodies that bind to surface polysaccharides or proteins, facilitating phagocytosis and clearance by the immune system [3][4].