CD4+ T-cell receptor recognizing influenza-derived peptides presented by MHC class II (CD4+ TCR (Influenza/MHC-II))

The CD4+ T-cell receptor (TCR) recognizing influenza-derived peptides presented by MHC class II is a fundamental mediator of the adaptive immune response to influenza virus infection. These TCRs are heterodimeric proteins that specifically bind to viral peptide fragments, such as those from hemagglutinin (HA) or nucleoprotein (NP), which are displayed by Major Histocompatibility Complex (MHC) class II molecules on the surface of antigen-presenting cells [PubMed: 28253175]. Upon recognition, the TCR initiates signaling pathways that lead to the activation and differentiation of CD4+ T cells into various effector subsets, including Th1 and T follicular helper (Tfh) cells [NIH: PMC4104054]. These cells are vital for providing 'help' to B cells for high-affinity antibody production and for enhancing the memory response of CD8+ cytotoxic T cells [PubMed: 31164461]. In clinical practice, this target is the focus of vaccine development, where the goal is to elicit TCR-mediated recognition of conserved viral epitopes to provide broad protection against multiple influenza strains [Nature: 10.1038/s41541-021-00354-z]. Therapeutic challenges include the high degree of HLA polymorphism in the human population, which dictates which peptides can be presented to these TCRs [PubMed: 25231621]. Furthermore, improper activation of these T cells can contribute to excessive inflammation or potential cross-reactivity with host tissues. Monitoring the frequency and specificity of these TCRs serves as a key biomarker for assessing vaccine efficacy and natural immunity.

Other names

Influenza-specific CD4+ T-cell receptorMHC class II-restricted influenza TCRTCR-MHC II influenza complexInfluenza-reactive CD4+ TCR

Activation of CD4+ T cells through the recognition of specific influenza-derived epitopes presented by MHC class II molecules, which triggers cytokine release and coordinates B-cell and CD8+ T-cell responses to clear the virus and establish immunological memory.