CD4+ T-cell receptor recognizing influenza hemagglutinin-derived peptides presented on MHC class II (HA-specific CD4+ TCR)

The CD4+ T-cell receptor (TCR) recognizing influenza hemagglutinin (HA)-derived peptides presented on MHC class II molecules is a specialized protein complex essential for the adaptive immune response against influenza viruses (PubMed: 31209223). These receptors, typically composed of alpha and beta chains, reside on the surface of CD4+ T helper cells and specifically bind to viral HA epitopes, such as the highly conserved HA306-318 peptide, when displayed by HLA-DR or other MHC class II molecules (UniProt: P01730). Upon recognition, the TCR triggers intracellular signaling via the CD3 complex, leading to T-cell activation, proliferation, and the secretion of cytokines like IFN-gamma and IL-2, which are vital for B-cell maturation and antibody production (NIH: NIAID). This receptor complex is the primary target of seasonal influenza vaccines, which aim to elicit a robust memory T-cell population to provide rapid protection upon viral exposure. In therapeutic development, these TCRs are being explored for TCR-engineered T-cell therapies to provide heterosubtypic immunity against multiple influenza strains. Monitoring the frequency and diversity of these HA-specific TCRs serves as a key biomarker for vaccine efficacy and immune longevity. However, therapeutic manipulation must account for potential cross-reactivity with self-peptides to avoid autoimmune complications.

Other names

Influenza HA-specific CD4+ TCRHemagglutinin-specific T-cell receptorHA-reactive CD4+ TCRMHC II-restricted HA-specific TCRHA-specific TCR

Recognition of influenza hemagglutinin peptides presented by MHC class II molecules triggers T-cell activation and the subsequent orchestration of the adaptive immune response.