Lipid molecules in cell membrane key to allergic response

March 8th, 2008 - 2:04 pm ICT by admin  

Washington, March 8 (ANI): In what may giver rise to improved diagnostic tests and treatments for allergy, a team of Penn State University researchers has for the first time shown that lipid molecules in cell membrane are key to mammals reactions to allergens in a living cell.

The researchers studied clusters of cholesterol-rich lipid molecules that are believed to serve as platforms for the receptors that receive antibodies, the proteins that protect the body from allergens.

They particularly examined IgE antibodies that, upon binding to their receptors, initiate a cell’s release of histamine the substance that causes the unpleasant but beneficial mucous production, congestion, and itchiness associated with allergies.

“This research is basically the molecular foundation for why many people sneeze in the spring,” said Ahmed Heikal, an associate professor in the Department of Bioengineering and a leader of the project.

Although the idea that lipid molecules are linked to allergic response is not new, the Penn State team is the first to document this connection in a living cell under physiological conditions.

“No one has observed the domains in action because they are too small and too transient–held together by very weak molecular interactions–to be viewed with a light microscope,” said Erin Sheets, a Penn State assistant professor of chemistry who also is a leader of the project.

Heikal added: To overcome this challenge, we used a combination of imaging and spectroscopy techniques that we are developing in our laboratories.

During the study, the researchers first labelled the cell membrane and IgE antibodies with two different fluorescent tags, and then introduced an allergen that bound to receptors on the cell membrane, thus initiating an allergic response.

The researchers took advantage of a property of fluorescence called fluorescence lifetime, in which molecules are excited with very short laser pulses, to show that the activity was taking place within the lipid domain.

They said that the results of their study show that lipid domains in the cell membrane associate with IgE antibodies and their receptors in the initial stages of an allergic reaction.”

The study has been reported in the Journal of Biological Chemistry. (ANI)

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