Streptococcus pneumoniae capsular polysaccharide conjugated to carrier protein

Streptococcus pneumoniae capsular polysaccharide conjugated to carrier protein represents a class of antigens in which the capsular polysaccharide (CPS) of specific S. pneumoniae serotypes is covalently attached to an immunogenic protein, typically a non-toxic mutant of diphtheria toxin (CRM197), tetanus toxoid, or other proteins. These polysaccharide–protein conjugates form the basis of pneumococcal conjugate vaccines (PCVs), which induce robust, T cell–dependent immune responses, including antibody class switching and immune memory, overcoming the limitations of plain polysaccharide vaccines that are T cell–independent and less effective in young children and the elderly. The immune response generated is critical for protection against invasive pneumococcal diseases (such as pneumonia, meningitis, and septicemia) caused by S. pneumoniae, making this conjugate a validated antigenic target in licensed vaccine formulations. The mechanism relies on B cell recognition of the polysaccharide, internalization of the entire conjugate, antigen processing/presentation of protein-derived peptides to T cells, and subsequent durable and affinity-matured antibody production. Multiple conjugate vaccines target different sets of serotypes; each conjugate molecule is specific to the polysaccharide and carrier protein combination. If you require more specific information pertaining to a single serotype or a particular carrier protein, please specify, as the above applies to the general class of Streptococcus pneumoniae capsular polysaccharide–protein conjugates.

Other names

Pneumococcal capsular polysaccharide–protein conjugateStreptococcus pneumoniae polysaccharide–protein conjugatePneumococcal conjugate vaccine antigenS. pneumoniae CPS conjugate

Carrier protein–mediated T-dependent immune response (polysaccharide antigens are covalently linked to immunogenic proteins, such as diphtheria toxoid CRM197, which enable T cell help, germinal center formation, antibody class switching, affinity maturation, and long-lived memory B cell generation). Elicits production of protective antibodies specific for capsular polysaccharide antigens of S. pneumoniae serotypes