Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances, such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens as being foreign to the body and produces antibodies that target the antigens.
Review Date:
7/3/2011 Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. |