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Immune response
Definition:
The immune response is how your body recognizes and defends itself against bacteria, viruses, and substances that appear foreign and harmful to the body. Alternative Names:
Innate immunity; Humoral immunity; Cellular immunity; Immunity; Inflammatory response; Acquired (adaptive) immunity Text Continues Below
Information:
The immune system protects the body from potentially harmful substances by recognizing and responding to so-called antigens. Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, or bacteria. Non-living substances such as toxins, chemicals, drugs, and foreign particles (such as a splinter) can be antigens. Substances that contain these antigens are recognized and destroyed by the immune system. Even your own body cells have proteins that are antigens. These include a group of antigens called HLA antigens. Your immune system learns to see these antigens as normal and does not usually react against them. BARRIERS AND INNATE IMMUNITY Your immune system includes barriers that keep harmful materials from entering your body. These barriers -- part of your innate (with you from birth) immunity -- form the first line of defense in the immune response. Some of these barriers are the skin, stomach acid, mucus (which traps bacteria and small particles), the cough reflex, and enzymes in tears and skin oils. If an antigen gets past the external barriers, it is attacked and destroyed by other parts of the immune system. BLOOD COMPONENTS The immune system includes certain types of white blood cells. It also includes chemicals and proteins in the blood, such as complement proteins and interferon. Some of these directly attack foreign substances in the body, and others work together to help the immune system cells.
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