fHBs-T84scFv-Fc

fHBs-T84scFv-Fc is a recombinant fusion protein designed to harness pre-existing immunity from Hepatitis B virus (HBV) vaccination for the treatment of colorectal cancer. The molecule is composed of a fragment of the Hepatitis B surface antigen (fHBs, amino acids 103-170) and a single-chain variable fragment (scFv) targeting Carcinoembryonic Antigen-Related Cell Adhesion Molecule 5 (CEACAM5/CEA), fused to an IgG Fc domain. The therapeutic strategy utilizes the T84scFv to target and internalize into CEA-positive tumor cells, delivering the HBsAg fragment for MHC presentation. This presentation triggers a potent recall response from anti-HBsAg CD8+ T cells present in HBV-vaccinated individuals, leading to targeted tumor cell lysis. Preclinical studies in mouse models have demonstrated that fHBs-T84scFv-Fc effectively binds to tumor cells and inhibits the growth of CEACAM5-positive tumors by increasing CD3+ and CD8+ T cell infiltration.