Classify antibodies into 5 types
There are 5 types of heavy chain constant regions in antibodies. The 5 types - IgG, IgM, IgA, IgD, IgE - (isotypes) are classified according to the type of heavy chain constant region, and are distributed and function differently in the body.
|IgG||IgG is the main antibody in blood. It is the only isotype that can pass through the placenta, and IgG transferred from the mother's body protects a newborn until a week after birth. IgG widely distributed to the blood and tissue, and protects the body.|
|IgM||IgM is made up of 5 antibodies. IgM has a key role in the initial immune system. It is distributed to the blood.|
|IgA||Secreted IgA is made up of 2 antibodies. It is distributed to serum, nasal discharge, saliva, breast milk and bowel fluid. Breast milk protects the gastrointestinal tract of newborns from bacterial and viral infection (maternal immunity).|
|IgD||IgD is present on the surface of B cells and plays a role in the induction of antibody production.|
|IgE||IgE is believed to be related to immunity reactions to parasites, and has recently become known as a key factor of allergies such as pollinosis.|
Population of 5 types of antibodies in blood (%)