Immunity Trigger is a term used to describe the process of activating the body's immune system. This is done by introducing an antigen, which is a foreign substance that stimulates the production of antibodies. Antigens can be proteins, toxins, or other molecules that are recognized by the body as being foreign. When an antigen is introduced, the body's immune system responds by producing antibodies that recognize and bind to the antigen, triggering an immune response.