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Web Date: June 24, 2014

Allergy Test Could Spot Unexpected Milk Allergens

Medical Diagnostics: Test can identify both common and unfamiliar milk allergens for a patient
Department: Science & Technology | Collection: Life Sciences
News Channels: Analytical SCENE, Biological SCENE
Keywords: milk allergy, allergen, IgE, immunoglobulin E, MALDI-MS, mass spectrometry, magnetic beads, component-resolved diagnostic

Not all milk allergies are created alike. Some folks get hives from caseins, while others wheeze after eating whey proteins. Nine of milk’s more than 25 proteins show a tendency to trigger allergic reactions, so traditional diagnostics generally screen just those nine. Now Swiss researchers offer a diagnostic that can pinpoint not only the troublesome nine, but also any unexpected allergens (Anal. Chem. 2014, DOI: 10.1021/ac500525n). The method offers a comprehensive allergy diagnosis, plus a promising way to track down entirely new allergenic proteins in foods and the environment.

To get to the source of a milk allergy, physicians often order a component-resolved diagnostic, an assay that determines whether known milk allergens bind to a patient’s immunoglobulin E (IgE) antibodies. These antibodies are the ones that can spark allergic reactions.

In the new test, Hubert H. Girault and Natalia Gasilova of the Swiss Federal Institute of Technology, Lausanne, made magnetic beads dotted with antibodies that bind all IgE antibodies in an allergic patient’s blood serum. The researchers then chemically cross-link the patient’s IgE antibodies to the beads. When they expose these personalized beads to milk, the patient’s own antibodies bind his or her particular allergens within the milk.

With matrix-assisted laser desorption/ionization mass spectrometry, the researchers then identify all bound allergens. This allows researchers to predict the structure of even unfamiliar allergens.

The scientists demonstrated the method by identifying one patient’s four milk allergens. Now they are adapting the technique to pollen, where they hope to discover novel allergenic proteins.

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Milk Allergen Tracker
Researchers run an allergic patient’s blood serum (top row) past a column of magnetic beads (orange circles) dotted with antibodies (black Y-shapes) that bind human immunoglobulin E (IgE) antibodies. The scientists next chemically crosslink any bound IgE antibodies (red Y-shapes) to the beads, then expose the now-personalized IgE-bound column to milk (bottom row). Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) identifies the mass and helps predict the structure of both familiar and unfamiliar bound milk allergens.
Credit: Natalia Gasilova
Schematic of method to detect known and unknown allergens in milk
 
Milk Allergen Tracker
Researchers run an allergic patient’s blood serum (top row) past a column of magnetic beads (orange circles) dotted with antibodies (black Y-shapes) that bind human immunoglobulin E (IgE) antibodies. The scientists next chemically crosslink any bound IgE antibodies (red Y-shapes) to the beads, then expose the now-personalized IgE-bound column to milk (bottom row). Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) identifies the mass and helps predict the structure of both familiar and unfamiliar bound milk allergens.
Credit: Natalia Gasilova
 
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ISSN 0009-2347
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