Introduction to Immunoglobulins
Vertebrates feature with a mighty immune system which is in charge in production of a variety of antibodies in case of presence of infective agents such as bacteria, viruses, parasites, fungi and certain chemicals. Antibodies are also produced in autoimmune diseases when they attack the very cells of the body since they are not able to recognize body cells as the part of the body. These antibodies are also known as immunoglobulins (Ig) and their role is neutralization of the foreign objects which enter the body and may jeopardize it. Immunoglubulins are produced by plasma cells, a type of white blood cells. They are made of heavy and light chains and according to the heavy chain all the immunoglobulins can be classified into several isotypes. These isotypes are IgA, IgD, IgE, IgG, and IgM.
IgE - Immunoglobulin E
This immunoglobulin was found in 1966 by the Japanese scientists Teruka and Kimishige Isjizaka.
Immunoglobulin E or IgE is a class of antibodies which is only produced in mammals. Its role is predominantly connected to allergies and stands in close relation to asthma and type 1 hypersensitivity. Its role is to protect the body against foreign objects, infective agents and allergens. This immunoglobulin is also associated with majority of parasitic worms including Schistosoma mansoni, Trichinella spiralis, Fasciola hepatica etc. It is essential in fight against certain protozoan parasites such as Plasmodium falciparum.
Immunoglobulin E is attached to the surface of mast cells. They raise an immune response after binding to Fc receptor which is located on the surface of basophiles and mast cells. Fc receptors can be also found on monocytes, eosinophils, macrophages and blood platelets. Once the foreign object, infective agent or allergen enters the body it is in the body and this represents a trigger for production of IgE antibodies.
In case of allergies when an antigen is detected by IgE an interaction between IgE receptors and IgE leads to production and release of certain chemicals called histamines, leukotrienes and iterleuikins. These chemicals are responsible for majority of symptoms of allergic reactions.
IgE can be easily measured after taking some blood samples. Normal concentration of IgE is low comparing to other antibody isotypes. The normal range of IgE is between 4.2 and 592 U/ml. The level above 592 U/ml is considered as high IgE concentration.
Elevated IgE levels are typical for people suffering from asthma, atopic dermatitis, certain types of cancers and in case of autoimmune diseases. High IgE levels are also a characteristic of Job syndrome, a rare immunodeficiency disorder. Atopic people may have up to 10 times bigger level of IgE than normal. They are prone to allergic illnesses and may develop asthma, hay fever and other allergic diseases.
Low levels of IgE are connected to rare immunodeficiency diseases and may also be a characteristic of a rare inherited illness called ataxia telangiectasia.