Streptococcus pneumoniae choline-binding proteins and non-capsular surface antigens (CBP)

Streptococcus pneumoniae choline-binding proteins (CBPs) and other non-capsular surface antigens are a heterogeneous group of proteins that play vital roles in the pathogenesis and physiology of the pneumococcus (Perez-Dorado et al., 2012, PMID: 22493231). CBPs, including Pneumococcal surface protein A (PspA) and C (PspC), are non-covalently attached to the cell wall choline residues and are involved in immune evasion by inhibiting complement deposition and facilitating adherence to host receptors like pIgR (UniProt P0A444, Q9S444). Other non-capsular antigens, such as the Pneumococcal histidine triad protein D (PhtD), are involved in metal ion homeostasis and are highly conserved across various pneumococcal serotypes (Plumptre et al., 2013, PMID: 23610146). Because these proteins are present in nearly all strains, they are being extensively researched as targets for protein-based vaccines to provide broader protection than current capsule-targeted conjugate vaccines (Pichichero, 2017, PMID: 28633556). Therapeutic strategies focusing on these antigens aim to induce broad-spectrum immunity that prevents colonization, pneumonia, and invasive pneumococcal disease. Experimental vaccines and monoclonal antibodies targeting these proteins are currently being evaluated for their ability to provide serotype-independent protection (NCT01204697).

Other names

Pneumococcal surface proteinsNon-capsular pneumococcal antigensCholine-binding protein familyPneumococcal surface protein A (PspA)Pneumococcal surface protein C (PspC)Pneumococcal histidine triad protein D (PhtD)Autolysin (LytA)

Induction of opsonophagocytic and neutralizing antibodies against conserved bacterial surface proteins to prevent colonization and invasive disease