Immunoglobulin E (IgE)
Reagin, Reaginic Antibody
One of five classes of
made by humans (the others being , ,
Main function seems to be to protect the host against invading parasites.
While parasitic disease may not be
a major clinical issue in most industrialized nations, it is a major public health problem in
developing nations. The antigen-specific IgE interacts with and to protect
the host against the invading parasite. However, the same antibody-cell combination is also responsible for
typical allergy or reactions such as ,
, and .
There are two major types of for the Fc portion (back) of the IgE or IgG4 molecule on .
One, a high receptor, is found primarily on
The other is a low affinity receptor found on cells.
IgE attaches to these and acts as an antigen receptor.
This class of immunoglobulins is distributed throughout the body, although cells synthesizing IgE
are found predominantly in association with mucosal tissues. IgE-bearing cells are also
found in large numbers in the neonatal ,
which on maturation revert to and IgM synthesis. Little is known of the traffic of
IgE-bearing or IgE-producing cells. If there is traffic of IgE cells it is less extensive
than the system - IgE is not found in breast milk, and only in very low amounts in other
secretions such as saliva.
Reagin is the allergist's term for IgE antibodies.