T cell receptor specific for Cross-reacting material 197-derived peptide–Major Histocompatibility Complex Class II complex (TCR-CRM197-MHCII)

T cell receptors (TCRs) on CD4+ T cells specific for CRM197-derived peptide–MHC II complexes are essential components of the adaptive immune response to conjugate vaccines (Pichichero, 2013, PMID: 23414949). CRM197 is a genetically detoxified mutant of diphtheria toxin that serves as a potent carrier protein, providing T-cell epitopes that are otherwise lacking in pure polysaccharide antigens (Bröker et al., 2011, PMID: 21763431). Upon vaccination, antigen-presenting cells process CRM197 and present its peptides via MHC Class II molecules to CD4+ T cells. The specific TCR recognition of these complexes triggers the activation of T follicular helper cells, which provide the necessary signals—such as CD40 ligand and cytokines—to B cells for isotype switching and memory formation (Avci et al., 2011, PMID: 21785434). This mechanism is the foundation for the efficacy of several blockbuster vaccines, including those against Streptococcus pneumoniae and Neisseria meningitidis. Understanding these TCR interactions is crucial for optimizing vaccine design and overcoming carrier-induced epitopic suppression (Broker et al., 2017, PMID: 28838784).

Other names

CRM197-specific T cell receptorCD4+ T cell receptor for CRM197Cross-reacting material 197-specific TCRTCR specific for CRM197-MHCII

Recognition of CRM197-derived peptides presented on MHC Class II by specific T cell receptors on CD4+ T cells, leading to T cell activation and the provision of help to B cells for high-affinity antibody production.