Truncated human CD19 protein (cell surface-expressed) (trCD19)

Truncated human CD19 protein (cell surface-expressed) refers to an engineered form of the human CD19 antigen, which lacks intracellular signaling domains, making it non-functional in normal immune signaling. When introduced and expressed de novo on the surface of non-B-cell tumor cells, it serves as a synthetic antigen, marking those cells for recognition and elimination by CD19-specific CAR-T cells. This strategy is used in research and emerging therapies to enable CD19 CAR-T cells—originally developed for B cell malignancies—to target a broader range of tumor types, especially solid tumors or other cancers that do not naturally express CD19. The truncated form is chosen to avoid unintended signaling or proliferation effects within the engineered tumor cells, while still providing a targetable extracellular epitope for CAR engagement. This target is not a naturally occurring molecule in these tumor types and is only present due to deliberate genetic modification of the cancer cells as part of a combination immunotherapy protocol. The main safety and efficacy challenges include ensuring selective antigen expression, monitoring for immune escape, and off-tumor activity in case of unintended expression in normal tissues.

Other names

trCD19truncated CD19CD19Δartificial/synthetic CD19 antigen

Enables immune recognition by CAR-T cells expressing anti-CD19 CARs. The CAR-T cells bind to the truncated CD19 epitope on the tumor cell membrane, leading to target cell killing.