Streptococcus pneumoniae surface protein A (PspA)

Streptococcus pneumoniae surface protein A (PspA) is a highly abundant choline-binding protein exposed on the bacterial surface and represents a major virulence factor. PspA inhibits activation of the host complement system (preventing deposition of C3b and C4b) and binds various host proteins such as lactoferrin, GAPDH, and lactate dehydrogenase, aiding immune evasion, iron uptake, and adhesion to dying host cells[1][2][3][4][5][6]. PspA additionally blocks killing by cationic antimicrobial peptides and promotes the aggregation and survival of pneumococcus within the respiratory tract, aiding in colonization, persistence, and transmission[2][4][5]. Due to its immunogenicity, PspA is the focus of extensive vaccine development efforts aimed at generating broadly protective antibodies, although its sequence variability across strains is a challenge for universal coverage[1][4][5].

Other names

Pneumococcal surface protein AS. pneumoniae PspA

Antibody-based therapies or PspA-based vaccines elicit immune responses that promote opsonization, complement-mediated killing, and phagocytosis of S. pneumoniae[1][3][4][5]