Comparison of in-house reference extracts of Dermatophagoides pteronyssinus and Phleum pratense with the WHO International Standards.
Two of the WHO First International Standards (IS) of allergenic extracts, the corresponding to Dermatophagoides pteronyssinus (House dust mite) and phleum pratense (Thymothy grass), have been used to assess the quality of our in-house reference preparations (IHR) and to calibrate their relative potency. The qualitative comparison was achieved by SDS-PAGE, Agarose-IEF and their respective enzime immunoblottings (Western blot and immunoprinting). The band patterns obtained were fairly similar for both Phleum pratense extracts. With the exception of two basic IgE binding proteins not detected in the IEF-blotting of the International Standard. However, several differences were noted between IS and IHR Dermatophagoides pteronyssinus extracts, indicating so the higher raw material heterogeneity. The difference was specially remarkable at the level of SDS-PAGE Immunoblotting since while our IHR extract showed similar ratio of Der p I to Der p II major allergens, the IS exhibited a large preponderance of Der p I, with Der p II allergen scarcely detected by our chromogenic method. Calibration of potency was done by means of RAST inhibition, therefore allowing the expression of our extract concentrations in International Units. The higher degree of homogeneity between Phleum pratense extracts was corroborated by the comparison of slopes from the RAST-inhibition plots.
Martínez
A
A
Ifidesa-Aristegui, Departamento de Investigación y Desarrollo, Bilbao, Spain.
Martínez
J
J
Llamazares
A
A
Palacios
R
R
D000485:Allergens / Q000276:immunology; D000818:Animals; D039741:Antigens, Dermatophagoides; D002138:Calibration; D015151:Immunoblotting; D007394:International System of Units; D007525:Isoelectric Focusing; D008925:Mites / Q000276:immunology*; D010936:Plant Extracts / Q000276:immunology; D006109:Poaceae; D011058:Pollen / Q000276:immunology*; D011852:Radioallergosorbent Test; D012015:Reference Standards; D014944:World Health Organization
D000485:Allergens; D039741:Antigens, Dermatophagoides; D010936:Plant Extracts