Diphtheria Toxin Mutant Protein Carrier (CRM197) (CRM197)

CRM197 is a genetically detoxified mutant of diphtheria toxin, specifically modified at position 52 (G52E). It serves as a carrier protein in conjugate vaccines, enhancing the immunogenicity of polysaccharides and haptens. It facilitates T-cell dependent immune responses and is a key component of vaccines against encapsulated bacteria like Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis. While retaining the structure and immunological properties of the native toxin, the mutation renders it non-toxic. It has also been investigated experimentally as a potential inhibitor of HB-EGF in cancer research.

Other names

Corynebacterium diphtheriae CRM197 proteinCross-Reactive Material 197

CRM197, when conjugated to poorly immunogenic antigens like polysaccharides, facilitates their presentation to T cells, converting a T-cell independent response to a T-cell dependent one, resulting in enhanced antibody production and immunological memory.