T-cell receptor-peptide-major histocompatibility complex class II (TCR-pMHC-II) (TCR-pMHC-II)

The T-cell receptor (TCR) recognition of peptide-Major Histocompatibility Complex class II (pMHC-II) is a fundamental event in the adaptive immune system, primarily involving CD4+ T cells (PubMed: 25033445). This interaction occurs when the TCR alpha and beta chains bind to a specific peptide fragment presented within the groove of an MHC-II molecule on professional antigen-presenting cells like dendritic cells or B cells (PubMed: 19707565). This recognition event is the primary signal for T-cell activation, leading to the orchestration of immune responses against pathogens or the maintenance of self-tolerance. Dysregulation of the TCR-pMHC-II interaction is central to the development of autoimmune diseases such as multiple sclerosis and rheumatoid arthritis, where self-antigens are incorrectly targeted (PubMed: 21248752). Conversely, in cancer, the failure of this recognition can lead to immune evasion. Therapeutic strategies targeting this complex include antigen-specific immunotherapies, such as glatiramer acetate which competes for MHC-II binding, and monoclonal antibodies like teplizumab that modulate the associated CD3 signaling complex (PubMed: 31412177).

Other names

TCR-MHC II complexT-cell receptor-HLA class II complexCD4+ T-cell receptor complexpMHC-II-TCR interaction

Antigen-specific binding of the TCR to the pMHC-II complex triggers the CD3 signaling apparatus, leading to the activation of ZAP-70 and the calcineurin/NFAT pathway (PubMed: 25033445).