Cross-reactive material 197 (CRM197) (CRM197)

Cross-reactive material 197 (CRM197) is a genetically detoxified mutant of the diphtheria toxin, widely employed as a carrier protein in conjugate vaccines [1]. It contains a single point mutation (G52E) that renders the toxin enzymatically inactive by preventing the binding of NAD+, yet it retains the ability to bind to the heparin-binding EGF-like growth factor (HB-EGF) receptor and remains highly immunogenic [2]. In the context of conjugate vaccines, CRM197 is chemically linked to polysaccharides; B cells specific to these antigens internalize the conjugate and present CRM197-derived peptides via MHC class II molecules to CD4+ T cells [3]. This interaction triggers T-cell-dependent immune pathways, including the release of cytokines and the activation of B cells, leading to high-affinity antibody production and immunological memory [2, 3]. CRM197 is a critical component of several vaccines targeting Streptococcus pneumoniae and Neisseria meningitidis [1]. Additionally, it is being investigated for its potential in anti-tumor therapies and as a delivery vehicle for crossing the blood-brain barrier [2]. Sources: [1] Shinefield, H. R. (2010). Vaccine, 28(27), 4335-4339. [2] Bröker, M., et al. (2011). Vaccine, 29(27), 4473-4481. [3] Avci, F. Y., et al. (2011). Nature Medicine, 17(12), 1602-1609.

Other names

Diphtheria toxin CRM197 mutantG52E diphtheria toxinCRM197 carrier proteinCross-reactive material 197

Acts as a carrier protein that provides T-cell epitopes to induce a T-cell-dependent immune response against conjugated haptens or polysaccharides, facilitating B-cell maturation and memory.