Antigen-presenting cell: A type of cell in the immune system that functions to alert other immune cells (e.g. T cells) when there is a threat to the body. The type and potency of the subsequent T cell response against the threat depends on the specific properties of the antigen-presenting cell and other factors.
Chimeric antigen receptor (CAR): An engineered protein where one end of the protein can bind to cancer cells, and the other end can send a signal to a T cell to kill the cancer cell. T cells from a patient’s blood can be modified in the lab so that they have CARs on their surface, and then the T cells can potentially be used as a type of therapy.

Clinical trial: A research study aimed at finding better ways to detect, treat or manage diseases.
Dendritic cell: A type of antigen-presenting cell that has the potential to activate strong T cell responses.
Immune system: The collection of different types of white blood cells, fluid, and organs such as spleen and lymph nodes, that serve the primary purpose of protecting the body from infection. The immune system can be harnessed to eliminate cancer.
PD-1: A protein that is sometimes present on the surface of T cells. When PD-1 is “triggered” by a protein called PD-L1, the T cell is shut down. Some of the new immunotherapy drugs are aimed at blocking the triggering of PD-1 by PD-L1. The end result is there is a “release of the brakes” on the cancer-fighting T cells.
T cell (T lymphocyte): A type of white blood cell in the immune system that has the ability to recognize and kill other cells, including cancer cells. If the other cell poses a threat to the body, then T cells can potentially destroy it.
T cell receptor (TCR): A protein on the surface of a T cell that allows the T cell to recognize and react against its targets.
Tumor-infiltrating lymphocytes (TILs): T cells that are found within a tumor mass. The populations of TILs are enriched for T cells that can function to kill cancer cells.