CD4+ T-cell receptor specific for Hemagglutinin-derived peptides presented on Major Histocompatibility Complex class II (HA-specific CD4+ TCR)

The CD4+ T-cell receptor (TCR) specific for hemagglutinin (HA)-derived peptides presented on Major Histocompatibility Complex (MHC) class II is a critical component of the adaptive immune system's defense against influenza viruses (PubMed: 25609815). These receptors, typically composed of alpha and beta polypeptide chains, reside on the surface of helper T cells and recognize specific 13-25 amino acid sequences from the HA protein, a major surface glycoprotein of the influenza virus (UniProt: P03468). Upon binding to the HA peptide-MHC class II complex on antigen-presenting cells, the TCR initiates signaling pathways that lead to T-cell proliferation and the secretion of pro-inflammatory cytokines like IL-2 and IFN-gamma (PubMed: 30206130). This process is essential for providing help to B cells for high-affinity antibody production and for the optimal activation of cytotoxic CD8+ T cells (Janeway's Immunobiology). In clinical practice, these TCRs are the primary targets of influenza vaccines, such as Fluzone and FluMist, which seek to elicit a robust and durable population of HA-specific memory T cells to prevent or mitigate infection (NIH/NIAID). Furthermore, research into the structural biology of these TCRs informs the development of universal influenza vaccines and novel T-cell-based immunotherapies (PubMed: 31511311).

Other names

Hemagglutinin-specific T-cell receptorHA-specific TCRInfluenza HA-specific CD4+ TCRMHC-II restricted HA-specific TCR

Agonistic stimulation of the TCR by vaccine-delivered HA peptides presented on MHC-II, leading to T-cell activation, expansion, and coordination of the adaptive immune response against influenza.