Which statement best describes CAR-T cell therapy?

• A. CAR-T therapy uses viral vectors to deliver PD-1 inhibitors.
• B. CAR-T Cell Therapy Is a Vaccine Approach.
• C. CAR-T Cell Therapy Uses Chemotherapy to Kill Cancer.
• D. CAR-T Cell Therapy Uses a Patient's T Cells Engineered With a Chimeric Antigen Receptor to Target Cancer.

Answer: (D)

CAR-T cell therapy starts with a patient’s own T cells, which are collected and then engineered in the lab to express a chimeric antigen receptor that can recognize a specific cancer protein. This receptor combines an antibody-like binding domain with T cell signaling parts, so when the modified T cells encounter cancer cells bearing the target antigen, they become activated, proliferate, and kill the cancer cells directly. After expansion, these engineered T cells are infused back into the patient, sometimes following a brief conditioning chemotherapy to make space for them. This approach is a form of adoptive cell transfer using the patient’s own cells, and it is distinct from vaccines (which stimulate the immune system rather than directly arming T cells) and from therapies that rely on checkpoint inhibitors or traditional chemotherapy to kill cancer cells.