Immunoglobulin E, referred to simply as IgE, is an antibody discovered in 1966 by Kimishige Ishizaka, founding president and first scientific director of the La Jolla Institute for Allergy & Immunology (LIAI). IgE is a critical component of allergic diseases, and its discovery was a breakthrough in the field of allergy research. IgE functions by binding itself in the body to a mast cell, another critical component in allergic disease. Once IgE is bound to mast cells, the mast cells are set into a "sensitized" condition. When an allergen is introduced into the body (something such as dust or pollen), it will bind to IgE on the sensitized mast cells and trigger an allergic reaction by secreting a variety of mediators such as histamine and cytokines, hormones for immune cells that cause what we traditionally call an allergic reaction.
IgE remains a key component of research here at LIAI, and the lab of Toshi Kawakami, M.D., Ph.D., has made an intriguing discovery that may change the way this critical antibody is looked at.
The Kawakami lab has unearthed a degree of heterogeneity (variation) in IgE, which could broaden the scope of allergy research. It had been thought that there was simply one type of IgE, and that it had a set behavior; a passive role in which it only served to sensitize mast cells. Kawakami's research may turn this idea on its head. After introducing IgE obtained from a variety of atopic (allergic hypersensitive) patients into a culture of mast cells, Kawakami's lab discovered that much of the IgE simply did not activate mast cells. Some of the IgE, though, triggered a full allergic reaction of mast cells as if they had been exposed to allergens. This proves that IgE on its own may be able to cause an allergic reaction, in the absence of an allergen. Therefore, Kawakami's lab has concluded that there are at least two types of IgE, one is a conventional sensitizer for mast cells and the other is a direct stimulant for mast cells.
This discovery has led to the lab beginning to examine IgE to better distinguish its varietals. How do different types of IgE affect the immune system? Learning more about the types of IgE could allow researchers to more efficiently target what allergies individuals could be susceptible to, simply by examining the sort of IgE present in one's immune system.
