CD4+ T-cell receptor (TCR) recognizing Cross-Reacting Material 197 (CRM197)-derived peptides presented by Major Histocompatibility Complex (MHC) class II (CRM197-specific TCR)

The CD4+ T-cell receptor (TCR) recognizing CRM197-derived peptides presented by MHC class II is a critical component of the adaptive immune response to conjugate vaccines. CRM197 is a non-toxic mutant of the diphtheria toxin (Gly52Glu) that serves as a potent carrier protein for polysaccharide antigens (Pichichero, 2013). When a conjugate vaccine is administered, antigen-presenting cells internalize the conjugate, process the CRM197 protein into peptides, and present them on MHC class II molecules (Broker et al., 2011). The specific TCRs on CD4+ T cells recognize these peptide-MHC complexes, leading to T-cell activation and the subsequent provision of cognate help to B cells. This interaction is essential for inducing high-affinity IgG antibodies and long-term immunological memory against the polysaccharide component of the vaccine (Avci et al., 2011). This mechanism is leveraged in numerous widely used vaccines, including those against Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b.

Other names

CRM197-specific T-cell receptorT-cell receptor for cross-reacting material 197CRM197-reactive TCRDiphtheria toxin-specific TCR

The TCR recognizes CRM197-derived peptides presented by MHC class II on antigen-presenting cells, triggering CD4+ T-cell activation and subsequent B-cell help for antibody production (Avci et al., 2011).