Anti-fluorescein isothiocyanate chimeric antigen receptor (anti-FITC CAR) (anti-FITC CAR)

The anti-fluorescein isothiocyanate (FITC) chimeric antigen receptor (CAR) is a synthetic modular receptor system used in adoptive cell therapy to enhance the control and versatility of T-cell treatments. Unlike conventional CARs that are permanently fixed to target a specific endogenous tumor antigen, the anti-FITC CAR is engineered to recognize the exogenous small molecule hapten FITC. This system operates via a 'switch' or 'adapter' mechanism, where FITC-conjugated monoclonal antibodies or small ligands are administered to bridge the CAR-T cell to the tumor cell (Kim et al., 2015). This design allows for the fine-tuning of T-cell activation by adjusting the adapter dosage and enables the targeting of multiple different antigens using a single CAR-T cell product (Lee et al., 2019). By decoupling the antigen recognition from the T-cell, the system provides a safety 'off-switch,' as the CAR-T cells return to a resting state once the FITC-labeled adapter is cleared from the circulation. This modularity is particularly useful for mitigating toxicities like cytokine release syndrome and overcoming tumor antigen escape (Ma et al., 2016).

Other names

FITC-specific CARFluorescein-directed CARModular CAR-T (FITC-based)Universal CAR (anti-FITC)FITC-labeled antibody-based CAR system

The anti-FITC CAR-T cell recognizes the FITC moiety on a bispecific adapter molecule (such as a FITC-conjugated monoclonal antibody), which bridges the T-cell to a tumor-associated antigen. This interaction induces T-cell receptor signaling through CD3-zeta and costimulatory domains (e.g., 4-1BB or CD28), leading to cytokine release and granzyme/perforin-mediated lysis of the target tumor cell (Tamada et al., 2012; Ma et al., 2016).