IgG binding of mugwort pollen allergens and allergoids exposed to simulated gastrointestinal conditions measured by a self-developed ELISAtest

This study considers the influence of exposure to simulated gastrointestinal condi- tions (saliva, gut, intestine and acidic conditions of the gut) on IgG binding of unmodified al- lergens and three types of LMW allergoids of Artemisia vulgaris pollen extract obtained by means of potassium cyanate, succinic and maleic anhydride. It also concerns the optimiza- tion of a self-developed ELISA assay for comparison of the specific IgG binding of mugwort pollen extract and modified mugwort pollen derivatives. The ELISA was con- ducted with a mugwort pollen extract coupled to the plate, using the sera from 12 mug- wort-pollen allergic patients. The exposure to saliva fluid for 2 min did not influence the IgG binding properties of allergens and allergoids. Exposure of mugwort pollen allergens and LMW allergoids to the acidic conditions of the gut did not dramatically change their IgG binding properties. By exposing mugwort pollen extract and LMW derivatives to the SGF conditions for 1 h, the percent of IgG binding epitopes was reduced to a half of its starting value in the extract and to about 30 % in all the allergoid samples. After prolonged exposure only the carbamyl derivative showed reduced IgG binding. Changes of the IgG binding po- tential of all four samples after exposure in SIF followed a similar pattern.