[Partial purification and analysis of allergenicity, immunogenicity of Ginkgo biloba L. pollen]

Pollens of Ginkgo biloba L. (G.b.l.p) have been found to be a kind of important allergen which causes pollinosis in Chengdu. The goal of this study is to purify G.b.l.p and to determine the allergenicity and immunogenicity of various fractions. Crude extract was purified by gel filtration with Sephadex G25, then G75. Two elution peaks were observed. On SDS-PAGE, the molecular weights of protein of the 1st peak and the valley were 30-42 kd and 13-18kd, respectively, and that of the 2nd peak was less than 13 kd. 40 patients with allergic rhinitis and/or asthma underwent the skin test with crude extract and various fractions of gel filtration; it revealed that the strongest allergenic activity existed in the 1st peak and there was mild allergenic activity in the 2nd peak. The in vitro allergenic activity and immunogenic activity of various fractions were examined by ELISA inhibition test. It was further confirmed that the allergenic activity and immunogenic activity of the 1st peak were the strongest, and those of the 2nd peak were the lowest. It is suggested that diagnosing reagents can be made satisfactorily by partial purification, i.e. discarding the inactive fractions, since allergenicity exists in various fragments. But fractions of allergen with high IgG immunogenicity should be selected to produce immunotherapy agents so as to enhance the production of blocking antibody and thus improve the therapeutic effect.