DETERMINATIONS OF PAR-J-1 BY A COMPETITIVE ENZYME-IMMUNOASSAY USING HUMAN SPECIFIC IGE AND IGG - VALIDATION BY SKIN PRICK TESTING

Par j 1 is the major allergen of Parietaria judaica. The objectives of this study were the following: I) to purify Parj 1; 2) to develop an enzyme immunoassay based on the bivalent properties of specific IgE an d IgG to determine the Parj I content in several batches of P. judaica extracts, and, 3) to study the contribution of Parj I to the total al lergenicity and antigenicity of P. judaica extracts. P, judaica pollen was extracted and subjected to hydrophobic interaction and gel filtra tion chromatography for the purification of Par j 1. Inhibition enzyme immunoassays, SDS-PAGE and immunoblotting were used to characterize t he allergen content The in vivo biological potency of the extracts was estimated by skin prick testing 26 P. judaica clinically sensitive pa tients. The new enzyme immunoassay showed a high degree of specificity and sensitivity, defecting from 2 to 100 ng Par j 1/ml. The range of Parj I content in nine batches ranged from 23% to 78% of the total pro tein in the extracts. The Par j I content showed a significant correla tion with the allergenic potency of these extracts evaluated by specif ic IgE inhibition and skin prick testing; the correlation with the spe cific IgG inhibition capacity was not significant. Purified Parj I sho ws great specific IgE and IgG binding capacity; its content can be det ermined using this newly developed enzyme immunoassay. Parj 1 levels e xhibit a significant correlation with the biological potency of the ex tracts. This method allows the detection of Parj I isoforms.