T cell receptor (TCR) recognizing influenza peptide–MHC class II complex (TCR-pMHCII)

The CD4 T cell receptor (TCR) recognizing influenza peptide–MHC class II complexes is a specialized heterodimeric protein complex essential for the adaptive immune response to influenza A and B viruses (Source: PubMed PMID 11836527). This receptor, typically composed of alpha and beta glycoprotein chains, specifically identifies viral epitopes—most notably the hemagglutinin (HA) 306-318 peptide—when presented by Major Histocompatibility Complex (MHC) class II molecules such as HLA-DRB1*01:01 (Source: PDB 1FYT). Upon recognition, the TCR initiates a signaling cascade through the CD3 complex, leading to the activation of CD4+ helper T cells which are vital for orchestrating B cell antibody production and enhancing cytotoxic T cell activity (Source: Janeway's Immunobiology). In drug development, this interaction is a primary target for 'universal' influenza vaccines designed to elicit broad, cross-reactive T-cell immunity across diverse viral strains (Source: NIH/NIAID). Furthermore, engineered TCR-T cell therapies are being explored to provide passive immunity or treat severe viral infections by leveraging these specific recognition motifs (Source: Frontiers in Immunology). Safety considerations for targeting this complex include the risk of molecular mimicry and cross-reactivity with self-peptides, which could lead to autoimmune responses or cytokine release syndrome (Source: Nature Reviews Immunology).

Other names

Influenza-specific CD4+ T cell receptorHA-specific TCRHemagglutinin-specific T-cell receptorTCR-HLA-DR-HA complexMHC class II-restricted influenza-specific TCR

The TCR specifically binds to influenza-derived peptides presented by MHC class II molecules on antigen-presenting cells, triggering intracellular signaling that leads to CD4+ T cell activation, proliferation, and the secretion of pro-inflammatory cytokines to coordinate viral clearance.