Antibody and Antigen

This antibody is found in body fluids such as tears, saliva, mucosa, and other bodily secretions. It is an antibody that provides a first line of defense against invading pathogens and allergens, and is the body's major defense against viruses. It is found in large quantities in the bloodstream and protects other wet surfaces of the body. While they have basic similarities, each IgA is further differentiated to deal with the specific types of invaders that are present at different openings of the body.