Antibodies consist of five types of heavy chains. Antibodies are of 5 types based on heavy chain.
- Immunoglobulin G (IgG): It is the smallest antibody. It is present in the blood, lymph and intestines. 75%-80% of the human body is IgG. IgG is the only antibody that can penetrate the placenta and enter the fetus. It inhibits bacteria and viruses in the process of opsonization. It also works in detoxification. It is of four types. Namely- IgG1, IgG2, IgG3 and IgG4.
- Immunoglobulin M (IgM): This is the largest antibody. It exists as a pentamer in the blood. 5%-10% of the human body is IgM. They destroy bacteria by the process of agglutination and bacteriolysis. It accelerates the process of phagocytosis. They are effective against polysaccharide antigens. This is Dudhran. namely IgM1 and IgM2.
- Immunoglobulin A (IgA): 15% of the body’s total antibodies are IgA. It is found in the digestive system, reproductive system, respiratory system and breast milk.
- Immunoglobulin D (IgD): This type of antibody is less in the body. Human body contains 0.2% IgD. They remain on the surface of B-lymphocytes as monomers and stimulate B-lymphocytes to produce antibodies.
- Immunoglobulin E (IgE): This type of antibody is very low in the body. The human body contains 0.1% IgE. They are present in the membranes of the lungs, skin, mucous, mast cells and basophil cells and accelerate histamine secretion. They protect the body from allergies.