B-lymphocyte antigen CD19-T-cell surface glycoprotein CD3 epsilon chain cell-cell interface (CD19-CD3) (CD19-CD3)

The B-lymphocyte antigen CD19-T-cell surface glycoprotein CD3 epsilon chain cell-cell interface (CD19-CD3) is a therapeutic target formed by the physical bridging of a B cell and a T cell, typically mediated by bispecific T-cell engagers (BiTEs) (Baeuerle & Reinhardt, 2009). CD19 is a cell surface molecule found almost exclusively on B cells, making it an ideal marker for B-cell malignancies, while CD3 is a critical component of the T-cell receptor complex required for T-cell activation (UniProt P15391, P07766). When a therapeutic agent like blinatumomab binds both CD19 and CD3, it creates an artificial immunological synapse that brings cytotoxic T cells into close proximity with target B cells (FDA, 2014). This interaction triggers the activation and proliferation of T cells, leading to the directed release of cytotoxic granules like perforin and granzymes into the B cell, resulting in its lysis (Klinger et al., 2016). This mechanism is highly effective because it bypasses the requirement for major histocompatibility complex (MHC) class I presentation, allowing T cells to recognize and kill tumor cells that might otherwise evade the immune system. Clinically, targeting this interface is a cornerstone in treating relapsed or refractory B-cell precursor acute lymphoblastic leukemia (B-ALL) and is being investigated for other B-cell-mediated diseases.

Other names

CD19/CD3 complexCD19-CD3 immunological synapseCD19-CD3 bispecific targetCD19xCD3 interaction

Bispecific T-cell engagement leading to redirected T-cell-mediated lysis of CD19-positive cells.