CD19 is an antigen protein expressed on the surface of various blood tumor cells, including B-cell lymphoma and leukemia cells, making it particularly suitable as a targeting site. Among these products, the single-chain antibody (scFv) within the CAR structure serves as the core component of the targeting system and plays a crucial role in enabling CAR-T cells to precisely eliminate tumor cells. FMC63, a murine monoclonal antibody targeting human CD19, has its scFv sequence widely used in multiple approved CAR-T therapies. The anti-idiotypic antibody Anti-FMC63 Antibody, which specifically binds to the FMC63 scFv, demonstrates low background noise, high specificity, and strong sensitivity, and is commonly employed for detecting CAR expression derived from the FMC63 scFv.
