Grass allergens : a preliminary characterization by means of RAST-based allergen assay methods

A preliminary study of a grass pollen allergens by means of radioallergosorbent test (RAST)-based assay methods has been made. A combination of gel filtration and ion exchange chromatography has been used to separate allergens, mainly from Festuca elatior, Lolium perenne, and Phleum pratense, into groups dependent on their molecular weight and net electric charges. A RAST-based titration method was used to detect and quantitate the different allergens. The specificity towards IgE of the different allergen groups was investigated by means of a RAST-based inhibition method. The allergen groups were found to be of a quite heterogenous nature when investigated by means of polyacrylamide gel electrophoreses. Furthermore, the different groups exhibited a considerable degree of cross-reactions when tested against a pool of patient sera by means of the inhibition method. This was the case even for allergen groups which differed significantly both in regard to molecular weight and net electric charge.