PATHOLOGY

Detailed explanation-1: -Antigens are substances (usually proteins) on the surface of cells, viruses, fungi, or bacteria. Nonliving substances such as toxins, chemicals, drugs, and foreign particles (such as a splinter) can also be antigens. The immune system recognizes and destroys, or tries to destroy, substances that contain antigens.

Detailed explanation-2: -Antigens are any substances that the immune system can recognize and that can thus stimulate an immune response. If antigens are perceived as dangerous (for example, if they can cause disease), they can stimulate an immune response in the body.

Detailed explanation-3: -In cell-mediated immune responses, the second class of adaptive immune response, activated T cells react directly against a foreign antigen that is presented to them on the surface of a host cell.

Detailed explanation-4: -The main job of the innate immune system is to fight harmful substances and germs that enter the body, for instance through the skin or digestive system. The adaptive (specific) immune system makes antibodies and uses them to specifically fight certain germs that the body has previously come into contact with.

Detailed explanation-5: -Exogenous antigens come from foreign substances that can enter your body through your nose, your mouth or cuts in your skin. These include viruses, bacteria, pollen, parasites and fungi.