W Fu1,2, Z Gao1,2, L Gao2, J Jin2, M Liu3, Y Sun4, S Wu1, L Wu3, H Ma3, Y Dong3, X Wang3, B Gao5, H Wang6, J H Akkerdaas7,8, S A Versteeg7,8, R van Ree7,8. 1. Allergy Research Center, Zhejiang University, Hangzhou, China. 2. Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China. 3. Department of Allergy, The Third People's Hospital of Datong, Shanxi, China. 4. Department of Allergy, Yu Huang Ding Hospital, Yantai, Shandong, China. 5. Research Department, Hangzhou Aileji Biotech Ltd, Hangzhou, China. 6. Department of Allergy, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China. 7. Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. 8. Department of Otorhinolaryngology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Abstract
BACKGROUND: Around 20 years ago, a 60- to 70-kDa protein was reported as a major allergen of mugwort (Artemisia vulgaris) pollen. This study was to identify and characterize its molecular properties. METHODS: Sera from 113 Chinese and 20 Dutch Artemisia-allergic/sensitized subjects (and pools thereof) were used to identify the 60- to 70-kDa allergen. Pollen extracts of seven Artemisia species were compared by immunoblotting. Transcriptomics and proteomics (mass spectrometry) of A. annua pollen were used to identify the putative 60- to 70-kDa Artemisia allergen. Both the natural purified and recombinant allergens were evaluated for IgE reactivity by ImmunoCAP. Fourteen Chinese Artemisia-allergic patients were tested intradermally with purified natural allergen. RESULTS: Immunoblots revealed two major bands at 12 and 25 kDa, and a weak band at 70 kDa for all seven Artemisia species. Using a combined transcriptomic and proteomic approach, the high molecular mass allergen in A. annua pollen was shown to be a 62-kDa putative galactose oxidase, with a putative N-glycosylation site. More than 94% of Artemisia pollen-allergic patients had IgE response to this allergen. Although recognition of a nonglycosylated recombinant version was only confirmed in a minority (16%) and at much lower IgE levels, this discrepancy cannot be explained simply by reactivity to the carbohydrate moiety on the natural allergen. Intradermal testing with the natural allergen was positive in five of nine sensitized patients. CONCLUSIONS: The previously reported 60- to 70-kDa allergen of Artemisia pollen is most likely a 62-kDa putative galactose oxidase here designated Art an 7.
BACKGROUND: Around 20 years ago, a 60- to 70-kDa protein was reported as a major allergen of mugwort (Artemisia vulgaris) pollen. This study was to identify and characterize its molecular properties. METHODS: Sera from 113 Chinese and 20 Dutch Artemisia-allergic/sensitized subjects (and pools thereof) were used to identify the 60- to 70-kDa allergen. Pollen extracts of seven Artemisia species were compared by immunoblotting. Transcriptomics and proteomics (mass spectrometry) of A. annua pollen were used to identify the putative 60- to 70-kDa Artemisia allergen. Both the natural purified and recombinant allergens were evaluated for IgE reactivity by ImmunoCAP. Fourteen Chinese Artemisia-allergicpatients were tested intradermally with purified natural allergen. RESULTS: Immunoblots revealed two major bands at 12 and 25 kDa, and a weak band at 70 kDa for all seven Artemisia species. Using a combined transcriptomic and proteomic approach, the high molecular mass allergen in A. annua pollen was shown to be a 62-kDa putative galactose oxidase, with a putative N-glycosylation site. More than 94% of Artemisia pollen-allergicpatients had IgE response to this allergen. Although recognition of a nonglycosylated recombinant version was only confirmed in a minority (16%) and at much lower IgE levels, this discrepancy cannot be explained simply by reactivity to the carbohydrate moiety on the natural allergen. Intradermal testing with the natural allergen was positive in five of nine sensitized patients. CONCLUSIONS: The previously reported 60- to 70-kDa allergen of Artemisia pollen is most likely a 62-kDa putative galactose oxidase here designated Art an 7.