IMMUNOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -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-3: -Foreign antigens originate from outside the body. Examples include parts of or substances produced by viruses or microorganisms (such as bacteria and protozoa), as well as substances in snake venom, certain proteins in foods, and components of serum and red blood cells from other individuals.

Detailed explanation-4: -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-5: -Antibodies are proteins made by the body’s natural defence system (immune system) to fight foreign substances, such as bacteria. Antibodies attach themselves to the foreign substance, allowing other immune system cells to attack and destroy the substance.