Factor VIII-specific T-cell receptor (FVIII-specific TCR)

Factor VIII-specific T-cell receptors (TCRs) are specialized heterodimeric surface proteins found on CD4+ T lymphocytes that recognize processed peptides of coagulation Factor VIII (FVIII) presented by Major Histocompatibility Complex (MHC) class II molecules (Pratt et al., 2017, Blood). In patients with Hemophilia A, these receptors are central to the development of 'inhibitors,' which are neutralizing alloantibodies that arise when the immune system identifies therapeutic FVIII replacement as a foreign antigen (Meeks and Batsuli, 2016, Blood). The binding of the FVIII-specific TCR to its cognate peptide-MHC complex triggers T-cell activation and provides essential signals to B cells for the production of high-affinity antibodies (Herzog et al., 2019, Frontiers in Immunology). Consequently, these TCRs are primary targets for tolerogenic therapies, such as peptide-based desensitization (e.g., ATX-F8) or the engineering of regulatory T cells (TCR-Tregs) designed to suppress the anti-FVIII immune response (Kim et al., 2015, Blood). Monitoring the frequency and phenotype of T cells bearing these receptors using MHC tetramers or ELISpot assays serves as a critical biomarker for assessing inhibitor risk and the efficacy of immune tolerance induction (De Groot et al., 2017, Expert Review of Hematology).

Other names

F8-specific T-cell receptorAnti-FVIII TCRFactor VIII-reactive T-cell receptorFVIII-specific CD4+ T-cell receptor

Induction of antigen-specific immune tolerance by modulating the activation, depletion, or suppression of CD4+ T cells that express TCRs specific for Factor VIII epitopes.