The views expressed in this article are the personal opinions of the authors and are not the official opinion of the U.S. Food and Drug Administration or the Department of Health and Human Services.
Characterization and comparison of commercially available German and American cockroach allergen extracts1
Article first published online: 2 MAY 2002
Clinical & Experimental Allergy
Volume 32, Issue 5, pages 721–727, May 2002
How to Cite
Patterson, M. L. and Slater, J. E. (2002), Characterization and comparison of commercially available German and American cockroach allergen extracts. Clinical & Experimental Allergy, 32: 721–727. doi: 10.1046/j.1365-2222.2002.01397.x
- Issue published online: 2 MAY 2002
- Article first published online: 2 MAY 2002
- Submitted 20 August 2001; revised 30 October 2001; accepted 24 January 2002
- Bla g 1;
- Bla g 2;
- relative potency;
- total protein content;
- German cockroach;
- American cockroach;
- allergen standardization;
- allergen extract
Background In this study we examine the variability among unstandardized cockroach allergen extracts.
Methods We obtained 24 aqueous and glycerinated cockroach allergen extracts from nine manufacturers. We used previously characterized cockroach extracts, E2-Cg and E2-Ca, as references. The modified ninhydrin assay was used to determine protein concentration of each extract. Relative potencies of extracts were determined by competition ELISA, using a human allergic serum pool. Bla g 1 and Bla g 2 levels of glycerinated German cockroach extracts were determined by ELISA using monoclonal antibodies. Extracts were also analysed by SDS-PAGE.
Results Commercial cockroach allergen extracts had highly variable protein contents that were lower than the protein contents of the references. Electrophoretic data confirmed the presence of a variable number and intensity of protein bands in extracts among manufacturers. The relative potencies of the commercial extracts were between 10 and 782 BAU/mL for German cockroach and 10–250 BAU/mL for American cockroach. The mean Bla g 1 content of the commercial extracts was significantly lower than that of the reference (P = 0.001). The mean Bla g 2 content of the commercial extracts was higher than that of the E2-Cg reference but the Bla g 2 levels were more variable compared to Bla g 1. In glycerinated German cockroach extracts, protein concentrations, relative potencies and specific allergen levels were significantly correlated (P < 0.001).
Conclusion Our tests indicate that commercially available cockroach allergen extracts are variable in protein content, electrophoretic banding patterns, relative potency and Bla g 2 levels. In glycerinated German cockroach extracts, protein concentrations, relative potencies and specific allergen levels were significantly correlated.