Ara h 2 and Ara h 6 have similar allergenic activity and are substantially redundant.
BACKGROUND
The moderately homologous (approx. 60%) proteins Ara h 2 and Ara h 6 are the most potent peanut allergens. This study was designed to define the relative individual contributions of Ara h 2 and Ara h 6 to the overall allergenic activity of a crude peanut extract (CPE).


METHODS
Ara h 2 and Ara h 6 were removed from CPE by gel filtration chromatography. Ara h 2.01, Ara h 2.02 and Ara h 6 were further purified (>99%). The potency of each allergen and the ability of these allergens to reconstitute the allergenic activity of CPE depleted of Ara h 2 and Ara h 6 was measured with RBL SX-38 cells sensitized with IgE from sensitized peanut allergic patients.


RESULTS
The potency of the native proteins were significantly different (p < 0.0001) although not dramatically so, with a rank order of Ara h 2.01 > Ara h 2.02 > Ara h 6. The addition of either purified Ara h 2 or Ara h 6 independently at their original concentration to CPE depleted of both Ara h 2 and Ara h 6 restored 80-100% of the original CPE allergenic activity. Addition of both Ara h 2 and Ara h 6 consistently completely restored the allergenic activity of CPE.


CONCLUSIONS
These studies indicate that either Ara h 2 or Ara h 6 independently can account for most of the allergenic activity in a CPE and demonstrate important redundancy in the allergenic activity of these related molecules.
Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado Denver, Aurora, CO 80045, USA.
Xueni
X
Chen
Qian
Q
Wang
Rabab
R
El-Mezayen
Yonghua
Y
Zhuang
Stephen C
SC
Dreskin
D055516:2S Albumins, Plant / Q000276:immunology* / Q000378:metabolism; D000485:Allergens / Q000009:adverse effects / Q000276:immunology*; D000818:Animals; D052179:Antigens, Plant / Q000276:immunology* / Q000378:metabolism; D010367:Arachis / Q000276:immunology; D001491:Basophils / Q000276:immunology; D045744:Cell Line, Tumor; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D021183:Peanut Hypersensitivity / Q000276:immunology*; D010936:Plant Extracts / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding; D051381:Rats
D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; C492737:Ara h 6 allergen, Arachis hypogaea; D006023:Glycoproteins; D010936:Plant Extracts; D007073:Immunoglobulin E