HLA class II molecules presenting CRM197-derived peptides (HLA-II/CRM197)

HLA class II molecules presenting CRM197-derived peptides are essential immunological complexes that mediate the efficacy of conjugate vaccines (Pichichero, 2013, PMID: 23333221). CRM197 is a genetically detoxified mutant of the diphtheria toxin (Gly52Glu) that serves as a potent carrier protein for poorly immunogenic antigens, such as bacterial polysaccharides (Bröker et al., 2011, PMID: 21763401). Upon administration, the CRM197-antigen conjugate is internalized by antigen-presenting cells or B cells, where CRM197 is proteolytically processed into peptides. These peptides are then loaded onto HLA class II molecules (primarily HLA-DR) and displayed on the cell surface. Recognition of these peptide-MHC complexes by the T-cell receptors of CD4+ helper T cells provides the necessary signals for B-cell isotype switching and the formation of high-affinity memory B cells (Avci et al., 2011, PMID: 22120174). This mechanism is the cornerstone of modern conjugate vaccine technology, ensuring robust and long-lasting immunity against various infectious pathogens.

Other names

MHC class II/CRM197 peptide complexHLA-DR/CRM197 complexCRM197-specific HLA-II complexesDiphtheria toxin CRM197-derived peptide-MHC II complexHLA-DRB1/CRM197 peptide complex

CRM197-derived peptides are loaded onto HLA class II molecules for presentation to CD4+ T-cell receptors, which triggers T-cell help for B-cell maturation and antibody production (Avci et al., 2011, PMID: 22120174).