A Comparison of the Antigenic and Allergenic Components of Birch and Alder Pollens in Scandinavia and Australia

Abstract

Allergens in birch (Betula) pollens from B. pendula grown in Australia and Norway, B. davurica and B. populofolia and from alder (Alnus incana) were identified by electroblotting, following separation by SDS-PAGE, transfer to nitrocellulose membranes and incubation with sera from birch pollen-allergic subjects. Of 42 antigenic components detected by protein staining in the pollen extract from B. pendula grown in Norway, 17 bound IgE. The allergenic components included those already reported in the literature at MWs of 40, 29, 25, 17 and 10-12 kd, as well as previously undescribed components at MWs of 90, 79, 60, 50, 38, 35, 31, 27, 23, 16, 15 and 14 kd. The major IgE-binding components were located in the low MW region 10-17 kd for all species of birch and alder pollen proteins studied. Results reported here provide the first evidence of birch and alder pollen allergies in Australia. Extensive heterogeneity was observed amongst the sera from birch pollen-allergic subjects in both Norway and Australia. Cross-reactivity appears to exist among the proteins present in pollen from the various birch species and from alder.