Immune Cell Gene Therapy Explained

Medically Reviewed by Melinda Ratini, MS, DO on March 06, 2024
2 min read

Immunotherapy is a cancer treatment that uses your immune system to find and kill cancer cells. There are different ways to make this happen, and immune cell gene therapy is one of those ways. It’s also called adoptive cell transfer, or ACT.                                                               

Genes are pieces of DNA inside a cell that tell the cell what to do. With immune cell gene therapy, genes in certain white blood cells are changed, or “reprogrammed,” so they can find and fight cancer cells in your body. Each person’s treatment is made using their own cells.

CAR (chimeric antigen receptor) T-cell therapy is the best understood form of immune cell gene therapy. It uses a kind of white blood cell called a T cell.

First, a machine filters T cells out of your blood, then it puts the blood back into your body. (This process is called apheresis.) The T cells are sent to a lab, where the genes inside them are changed: They’re told to make proteins called CARs. CARs are like keys on the outside of the T cell -- they fit in the “locks” on the cancer cells. Then the T cells are frozen and sent to your doctor.

The thawed cells are given back to you through an IV (this puts them right into your bloodstream through a vein). The CAR T cells travel through your body to find, lock onto, and kill cancer cells.

CAR T cells will grow and divide many times inside your body and may fight cancer cells for months or even years.

T-cell receptor (TCR) therapy is a lot like CAR T-cell therapy, but these T cells can find the “locks” that may be hidden inside cancer cells.

Tumor-infiltrating lymphocytes (TILs) are white blood cells that are found inside a tumor. This is a sign that your immune system is trying to attack and kill cancer cells.

TILs are taken out of the tumor and sent to a lab. They don’t need to be changed or reprogrammed. The lab technicians just make more of them to fight the disease. When large numbers of them are put back in your body, they find and kill the cancer cells.

A newer strategy is to use Natural Killer (NK) cells. Some scientists are outfitting NK cells with cancer-targeting CARs.