ANATOMY

Detailed explanation-1: -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.

Detailed explanation-2: -The difference between antigen and pathogen is easy to understand: An antigen is a substance that triggers the production of antibodies. Pathogens are harmful microorganisms that can cause diseases.

Detailed explanation-3: -An antigen is a foreign substance that enters your body. This can include bacteria, viruses, fungi, allergens, venom and other various toxins. An antibody is a protein produced by your immune system to attack and fight off these antigens.

Detailed explanation-4: -There are three types of antigens, classified based on where they are produced. Self-antigens, or autoantigens, are produced in the body’s own cells; endogenous antigens are produced in intracellular bacteria or viruses; exogenous antigens are produced outside the body and are foreign to the immune system.