Streptococcus pneumoniae conserved surface antigens

Streptococcus pneumoniae conserved surface antigens are a diverse group of proteins located on the outer surface of the pneumococcal cell wall that exhibit high sequence stability across various serotypes (Kadioglu et al., 2008). Unlike the variable capsular polysaccharides used in current vaccines, these proteins are essential for the bacteria's virulence and survival, performing functions such as nutrient acquisition, host cell adhesion, and evasion of the complement system (Perez-Dorado et al., 2012). Prominent examples include Pneumococcal surface protein A (PspA), which inhibits complement deposition, and Pneumococcal surface adhesin A (PsaA), which is vital for manganese transport and adherence (Giefing et al., 2008). These antigens are currently being investigated as primary components for next-generation, serotype-independent vaccines designed to provide broader protection than existing conjugate vaccines (Converso et al., 2020). By eliciting opsonophagocytic antibodies and cellular immune responses, targeting these conserved proteins aims to reduce the global burden of pneumococcal diseases like pneumonia and meningitis regardless of the infecting strain's capsule type (Pichichero, 2017).

Other names

Pneumococcal surface proteinsConserved pneumococcal antigensPneumococcal protein vaccine candidatesPneumococcal surface components

Vaccines targeting these antigens induce the production of opsonophagocytic antibodies and activate T-cell responses, which neutralize the functional activity of the surface proteins and facilitate the clearance of Streptococcus pneumoniae by the host immune system (Converso et al., 2020).