Streptococcus pneumoniae serotype 9V capsular polysaccharide-specific B cell (9V-specific B cell)

Streptococcus pneumoniae serotype 9V capsular polysaccharide-specific B cells are a specialized population of B lymphocytes that possess surface receptors (BCRs) capable of recognizing the unique glycan structure of the 9V serotype capsule (Centers for Disease Control and Prevention, 2022). These cells are essential for the host's defense against invasive pneumococcal disease (IPD), as they differentiate into plasma cells that secrete antibodies to neutralize and opsonize the pathogen (World Health Organization, 2019). Serotype 9V is historically associated with high rates of antibiotic resistance and is a frequent cause of pneumonia and meningitis globally (StatPearls, 2023). In clinical practice, these B cells are the primary immunological target of both polysaccharide and conjugate pneumococcal vaccines, such as PCV13 and PPSV23 (U.S. Food and Drug Administration, 2021). When exposed to vaccine antigens, these cells undergo clonal expansion and, in the case of conjugate vaccines, receive T-cell help to form long-lived memory B cells (PubMed, 2020). The induction of these specific B cells is a key correlate of protection for public health immunization programs. Monitoring their response is vital for assessing the long-term efficacy of vaccines and the potential for serotype shifting in the population. These cells are characterized by their ability to produce high-affinity IgG antibodies following successful vaccination (PubMed, 2018).

Other names

Pneumococcal serotype 9V-specific B lymphocyteAnti-9V B cellS. pneumoniae 9V CPS-specific B cell9V-specific B lymphocyte

The target B cells are activated through the binding of their surface B-cell receptors (BCRs) to the 9V capsular polysaccharide antigen (PubMed, 2020). In conjugate vaccines, the polysaccharide is linked to a carrier protein (e.g., CRM197), which facilitates T-cell dependent activation, leading to affinity maturation, isotype switching to IgG, and the generation of long-lived memory B cells (Centers for Disease Control and Prevention, 2022).