MIT engineers have developed a way to reprogram natural killer, or NK, cells without removing them from the body. These immune cells receive messenger RNA, which carries instructions for making proteins, through tiny fat-based particles. The proteins help the cells recognize and destroy their targets. Changing cells inside the body could avoid the time and expense of preparing them in a laboratory.
In mouse experiments, the particles reprogrammed about 80 percent of the targeted NK cells. Three of five treated mice with an aggressive form of melanoma, a skin cancer, went into complete remission, meaning the cancer disappeared. In another experiment, tumors from T cell lymphoma disappeared after five injections. Those mice had received human blood cells to give them a temporary human-like immune system.
The team also tested mice with autoimmune hepatitis, a disease in which T cells attack the liver. After one injection, the harmful T cells were destroyed and liver damage healed. The modified cells are called CAR NK cells. Although researchers are developing them for cancer and autoimmune diseases, no CAR NK treatments currently have approval from the US Food and Drug Administration.
