Video 16 Antibody Immunoglobulin Immune Function

16) Immunoglobulin Function of the five antibodies

Let's take a closer look at the five types of antibody immunoglobulins.

IgAs are not typically found in the blood, but in secretions of the gut, saliva, sweat, milk, respiratory track, and urinary track. IgAs are part of our innate immunity and fight pathogens, such as bacteria, viruses, fungus and worms. There are two types of IgAs.

IgDs are primarily found on the surface of B-cells and account for a very tiny portion of the free floating antibodies found in plasma. And while IgDs are the least well know antibody, they are known to play a role in the activation of basophils and mast cells to attack invading microbes.

IgEs respond to allergens, such as pollen as well as parasitic worms. IgEs bind to mast cells and basophils. Once the IgE receptor comes into contact with one of these antigens the mast cells and basophils will release histamine molecules, causing the inflammatory symptoms we know as an allergic reaction.

There are four types of IgGs. IgGs target pathogenic organisms, such as bacteria, viruses and parasites. They attach to an antigen on one end while the opposite end binds with phagocytic white cells (macrophages, neutrophils, and natural killer cells) to absorb and destroy the antigen. IgGs are the primary antibody of the human body, accounting for 70-80% of the entire immunoglobulin pool. It is the smallest Ig molecule, allowing it to easily migrate into the tissues of the body. Only 45% are found in the blood. Almost every man made monoclonal antibody in clinical use is in the IgG family.

IgMs are early responders and function to eliminate pathogens early on in the attack before there are sufficient levels of IgGs. IgMs are known as a macroglobulin because of their large size. They are the largest of the immunoglobulins and make up 6-10% of the total Ig pool.