Immunologic determination of the major allergen, Cry j 1, in Cryptomeria japonica pollen of 117 clones in Toyama prefecture: Some implications for further forestry research in pollinosis prevention

Background: A number of recent studies have clarified the characteristics of major allergens of Cryptomeria japonica, such as the locality, molecular weights of Cry j 1 and Cry j 2 and cross-reactivity with some other species of pollen. However, in order to plant C. japonica forests with low allergen levels, there is still a shortage of fundamental data for forest breeding. Methods: To obtain the some fundamental data concerning Cry j 1, three items were investigated: (i) variations in weight and Cry j 1 content per single pollen grain among 117 clones; (ii) environmental factors affecting Cry j 1 content; and (iii) genotype variations of Cry j1. Results: Although the variation in weight per single pollen grain among 117 clones was relatively small (mean (±SD) 10.2 ± 0.1 ng), the Cry j 1 content was found to vary widely from 0.26 to 7.54 pg. The expression level of Cry j 1 was higher in samples collected from lower altitudes. Using western blotting, it was shown that there were two Cry j 1 genotype variations. Conclusions: From these results, we have concluded that immunologic determination of Cry j 1 by individual pollen grain levels provides useful data, especially for forest breeding to prevent pollinosis