Streptococcus pneumoniae Capsular Polysaccharide Antigens Conjugated to Diphtheria CRM197 Protein Carrier (Pneumococcal Polysaccharide-CRM197 Conjugate)

The capsular polysaccharide antigens from various serotypes of *Streptococcus pneumoniae* are chemically conjugated to CRM197, a genetically detoxified mutant of diphtheria toxin. This conjugation is used in the formulation of pneumococcal conjugate vaccines (such as Prevnar), which are designed to induce a robust and long-lasting immune response against *S. pneumoniae* by converting the normally T-cell independent polysaccharide antigens into T-cell dependent forms. CRM197 is a non-toxic mutant form of diphtheria toxin produced by a single amino acid substitution (Glycine to Glutamic acid at position 52), which abolishes its ADP-ribosyltransferase activity while retaining immunogenicity. The resulting glycoconjugate stimulates both B cells and helper T cells, leading to stronger antibody production and immunological memory.

Other names

Streptococcus pneumoniae [serotype] capsular polysaccharide-diphtheria crm197 protein conjugate antigenPneumococcal [serotype] glycoconjugateCorynebacterium diphtheriae crm197 proteinCRM197-conjugated pneumococcal polysaccharide

Active immunization; induction of T-cell dependent immune response against Streptococcus pneumoniae capsular polysaccharides via presentation by CRM197 carrier protein, leading to B-cell activation and antibody production.