T-cell receptor recognizing influenza virus-derived peptide–MHC-II complexes (Influenza-specific TCR)

The T-cell receptor (TCR) recognizing influenza virus-derived peptide–MHC-II complexes is a specialized alpha-beta (αβ) heterodimer found on the surface of CD4+ T helper cells. It plays a pivotal role in the adaptive immune response by specifically identifying viral antigens, most notably the immunodominant hemagglutinin (HA) peptide (residues 306-318), when presented by Major Histocompatibility Complex class II (MHC-II) molecules such as HLA-DR1 or HLA-DR4 (Reinherz et al., 1999; Hennecke et al., 2000). This molecular recognition event is the primary trigger for T-cell activation, leading to the secretion of cytokines like interferon-gamma (IFN-γ) and providing the necessary signals for B-cell maturation and antibody production (Brown et al., 1991). In therapeutic contexts, these TCRs are the focus of TCR-engineered T-cell (TCR-T) therapies and the design of epitope-specific vaccines aimed at providing broad protection against various influenza strains (NIH, 2023). Structural studies of the HA1.7 TCR clone have provided fundamental insights into how the immune system discriminates between viral and self-peptides, which is essential for minimizing off-target effects and developing safe immunotherapies (PubMed, 1717572). Understanding the structural basis of this interaction is vital for predicting cross-reactivity and improving the efficacy of seasonal and universal influenza vaccines.

Other names

Influenza-specific CD4+ T-cell receptorHA-specific T-cell receptorHA1.7 TCRHemagglutinin-specific T-cell receptorInfluenza-specific TCRαβ

The T-cell receptor (TCR) specifically recognizes and binds to an influenza-derived peptide, such as the immunodominant hemagglutinin (HA) 306-318 epitope, when it is presented by Major Histocompatibility Complex class II (MHC-II) molecules (e.g., HLA-DR1 or HLA-DR4) on the surface of antigen-presenting cells. This binding event, stabilized by the CD4 co-receptor, triggers the phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) within the associated CD3 complex. This initiates a downstream signaling cascade involving ZAP-70 and PLC-gamma-1, leading to T-cell proliferation, the secretion of pro-inflammatory cytokines like IFN-gamma, and the coordination of the adaptive immune response to clear the viral infection.