How do T cells work?

The foundation of CAR T cell therapy lies in the white blood cells known as T lymphocytes or T cells. These T cells, a vital part of the adaptive immune system, are our body’s frontline defenders against infection and disease. Equipped with receptors that act as sensors, T cells can identify specific antigens, which are foreign substances or molecules in the body. Once these antigens are recognized, T cells spring into action, initiating an immune response that either stimulates antibody production or directly targets the cells that are hiding foreign molecules.

T cells are powerful because they are remarkably specific; each T cell is designed to address a particular threat. When T cells are activated, they multiply and differentiate. Some T cells separate to address the infection, while others preserve a memory of the pathogens (disease-causing organisms) to help the body recognize and respond if they reappear in the future. The natural ability of T cells to target specific threats, combined with the potential for researchers to manipulate them to target specific antigens, makes T cell-based therapies promising tools in combating disease.

The science behind CAR T technology

Chimeric antigen receptor T cells or CAR T cells are immune cells that are altered or genetically modified to recognize and remove cancer cells from the body. The process involves adding a chimeric antigen receptor to a patient’s T cells, which is designed to identify specific proteins or antigens on the surface of cancer cells. Once the modified T cells are reinfused into the patient’s bloodstream, they seek out and destroy the cancer cells. Our scientists develop various types of CAR T cells to target specific cancer antigens, as different types of cancer have different antigens.

Engineering T cells for a customized defense

The process of creating CAR T cells involves several steps. From the manufacturing of the chimeric antigen receptor to the reinfusion of newly created CAR T cells, the entire process may take several weeks. The process includes:

• Designing the chimeric antigen receptor: Our scientists develop a complex protein combination, also known as a CAR, that will enable T cells to recognize cancer cells. 
• Collecting the T cells: We collect blood from a vein in your arm or a central line, if you have one. The blood flows through a tube into an apheresis machine, which removes T cells. The machine returns the rest of the blood back into your body through a different tube. 
• Introducing the CAR: In a laboratory, scientists engineer the T cells by adding a manufactured CAR. Then the lab lets the CAR T cells multiply and grow. 
• Activating and expanding modified cells: We then activate and expand the modified T cells, encouraging the cells to differentiate into specialized subtypes via a cytokine treatment that enhances the cells’ tumor-targeting capabilities. 
• Preserving the CAR T cells: We concentrate the CAR-T cells, freeze them, and transport them back to the clinic for patient infusion.

CAR T cell therapy represents a cutting-edge approach to cancer treatment, and Penn Medicine is at the forefront of this innovation. Our team of specialists is dedicated to engineering these powerful T cells, precisely targeting specific cancers. This personalized approach harnesses the body’s natural defenses and equips them to precisely eliminate cancer cells. With ongoing research and development, Penn Medicine is committed to pushing the boundaries of CAR T-cell therapy, offering patients the most effective and personalized treatments possible.