Streptococcus pneumoniae capsular polysaccharide serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, 23F (PCV10 antigens)

The target consists of the capsular polysaccharides from ten specific serotypes of Streptococcus pneumoniae: 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F [EMA, https://www.ema.europa.eu/en/medicines/human/EPAR/synflorix]. These polysaccharides are the primary virulence factors of the bacterium, forming a protective outer layer that inhibits host opsonophagocytic clearance by preventing complement deposition and neutrophil recognition [NIH, https://pubmed.ncbi.nlm.nih.gov/30894445/]. In the context of therapeutics, these polysaccharides serve as the antigenic components of the 10-valent pneumococcal conjugate vaccine (PCV10), such as Synflorix [GSK, https://gskpro.com/content/dam/global/hcpportal/en_GB/products/Synflorix/pdf/Synflorix-PI.pdf]. When conjugated to carrier proteins like protein D from Haemophilus influenzae, tetanus toxoid, or diphtheria toxoid, they induce a T-cell dependent immune response [CDC, https://www.cdc.gov/vaccines/pubs/pinkbook/pneumo.html]. This process leads to the production of serotype-specific IgG antibodies and the establishment of immunological memory [NIH, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9351524/]. The resulting immunity provides protection against invasive pneumococcal diseases (IPD) like meningitis and sepsis, as well as non-invasive infections such as pneumonia and acute otitis media [EMA, https://www.ema.europa.eu/en/documents/product-information/synflorix-epar-product-information_en.pdf]. Clinical efficacy is typically monitored through biomarkers such as serotype-specific IgG concentrations and opsonophagocytic activity (OPA) titers [NIH, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3416086/]. While highly effective, the use of vaccines targeting these specific serotypes can lead to serotype replacement, where non-vaccine strains become more prevalent in the community [NIH, https://pubmed.ncbi.nlm.nih.gov/20133700/].

Other names

Pneumococcal capsular polysaccharides (serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, 23F)PCV10 antigensSynflorix antigensStreptococcus pneumoniae polysaccharides10-valent pneumococcal conjugate vaccine antigens

Active immunization; induction of serotype-specific opsonizing antibodies (IgG) that facilitate phagocytosis and killing of the bacteria [EMA, 2023; CDC, 2022].