antifolate
A type of drug that stops cells from using folic acid to make DNA and may kill cancer cells. Certain antifolates are used to treat some types of cancer and inflammatory conditions, such as rheumatoid arthritis. Also called folate antagonist and folic acid antagonist.
antigen
Any substance that causes the body to make an immune response against that substance. Antigens include toxins, chemicals, bacteria, viruses, or other substances that come from outside the body. Body tissues and cells, including cancer cells, also have antigens on them that can cause an immune response. These antigens can also be used as markers in laboratory tests to identify those tissues or cells.
antigen-presenting cell
A type of immune cell that boosts immune responses by showing antigens on its surface to other cells of the immune system. An antigen-presenting cell is a type of phagocyte. Also called APC.
antigen-presenting cell vaccine
A vaccine made of antigens and antigen-presenting cells (APCs). APCs boost an immune response by presenting antigens on their surfaces to other cells of the immune system. Also called APC vaccine.
antiglobulin test
A laboratory test to identify antibodies that can bind to the surface of red blood cells or platelets and destroy them. This test is used to diagnose certain blood disorders in which patients make antibodies to their own red blood cells or platelets. It is also used to determine blood type. Also called Coombs test.
antihistamine
A type of drug that blocks the action of histamines, which can cause fever, itching, sneezing, a runny nose, and watery eyes. Antihistamines are used to prevent fevers in patients receiving blood transfusions and to treat allergies, coughs, and colds.
antihormone therapy
Treatment with drugs, surgery, or radiation in order to block the production or action of a hormone. Antihormone therapy may be used in cancer treatment because certain hormones are able to stimulate the growth of some types of tumors.
antihypertensive agent
A type of drug used to treat high blood pressure. There are many different types of antihypertensive agents, and they work in different ways to lower blood pressure. Some remove extra fluid and salt from the body. Others relax and widen the blood vessels or slow the heartbeat. A person may respond better and have fewer side effects with one drug than with another. Some patients need more than one antihypertensive agent to lower their blood pressure.
antilymphocyte globulin
Serum from blood that contains antibodies that bind to human T cells. Antilymphocyte globulin is given to a patient before a stem cell transplant to kill T cells and lower the risk of graft-versus-host disease (GVHD). It is also used to treat GVHD and after a kidney transplant to help keep the body from rejecting the kidney. Also called antithymocyte globulin.