To understand CAR-NK cell therapy, a brief history of immunology may prove helpful. An antigen is either a toxin or disease agent or unhealthy cell (as in cancer), that triggers an immune response.
An antigen is a protein structure on the surface of the cell. These antigens serve as an identification signal. When a foreign antigen is detected in the body, either from a virus or a mutated cell (as in cancer), it triggers an immune response.

The body then produces white blood cells to attack the agent. It does this by binding to it with the use of antigen receptors on the surface of the white blood cells, or lymphocytes. Only then does the body produce antibodies to destroy the foreign or diseased agent.

The problem is that immune cells such as NK cells, are not always able to recognize and eliminate cancer. Therefore, to increase a patient’s immune levels, medical specialists collect blood, harvest NK cells, and add specific antigen receptors to the surface of these cells. Then, they inject the cells back into the patient via blood transfusion, where they multiply and can attack the cancer, either with or without the aid of additional therapies.

Thanks to the antigen-receptor, the immune cells can recognize specifically their target. By knowing which proteins (antigens) to look for, the modified NK cells can hunt them down, attack, and destroy them throughout the bloodstream.

With CAR-NK Cell Therapy, a patient’s (or the donator’s) NK cells are modified within a laboratory, so that they can find and attack cancer cells. Natural killer cells that have been genetically altered into CAR-NK cells function as the immune system’s guardians when they are administered to patients.