Heterogeneity of commercial timothy grass pollen extracts.
BACKGROUND
The diagnosis and specific immunotherapy of allergy is currently performed with allergen extracts prepared from natural allergen sources.


OBJECTIVE
To analyse commercial timothy grass pollen allergen extracts used for in vivo diagnosis regarding their qualitative and quantitative allergen composition and in vivo biological activity.


METHODS
Antibodies specific for eight timothy grass pollen allergens (Phl p 1, Phl p 2, Phl p 4, Phl p 5, Phl p 6, Phl p 7, Phl p 12, Phl p 13) were used to detect these allergens in timothy grass pollen extracts from four manufacturers by immunoblotting. ELISA assays were developed and used to quantify the three major allergens (Phl p 1, Phl p 2, Phl p 5) in the extracts. The magnitude of skin responses to the four extracts was studied by skin prick testing in 10 grass pollen-allergic patients.


RESULTS
The allergen extracts showed broad variations in protein compositions and amounts (24.1-197.7 microg/mL extract). Several allergens could not be detected in certain extracts or appeared degraded. A considerable variability regarding the contents of major allergens was found (Phl p 1: 32-384 ng/mL; Phl p 2: 1128-6530 ng/mL, Phl p 5: 40-793 ng/mL). Heterogeneous skin test results were obtained with the extracts in grass pollen-allergic patients.


CONCLUSIONS
Timothy grass pollen extracts from different manufacturers exhibit a considerable heterogeneity regarding the presence of individual allergens and hence yield varying in vivo test results. Problems related to the use of natural grass pollen allergen extracts may be circumvented by using defined recombinant grass pollen allergens.
Christian Doppler Laboratory for Allergy Research, Department of Pathophysiology, Center for Physiology and Pathophysiology, Vienna General Hospital, Medical University of Vienna, Austria. margarete.focke-tejkl@meduniwien.ac.at
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Focke
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Marth
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Flicker
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Valenta
D000486:Allergy and Immunology / Q000592:standards*; D052179:Antigens, Plant / Q000032:analysis* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015151:Immunoblotting; D031784:Phleum / Q000737:chemistry* / Q000276:immunology; D010936:Plant Extracts / Q000737:chemistry* / Q000627:therapeutic use; D011058:Pollen / Q000737:chemistry* / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000276:immunology / Q000628:therapy; D012882:Skin Tests / Q000379:methods / Q000592:standards
D052179:Antigens, Plant; D010936:Plant Extracts