Changes in quantity of Cry j1, a major cedar pollinosis allergen, in Cryptomeria japonica pollen during spring in Japan

The changes in quantity of Cry j1 in Cryptomeria japonica pollen were assessed during the course of spring in Japan. C. japonica pollen was collected from the same trees in Hiroshima and Yamanashi Prefectures, and Cry j1 was quantified by enzyme-linked immunosorbent assay. The quantities of Cry j1 were found to gradually decrease, and this trend was similar in both Hiroshima and Yamanashi Prefectures. In Yamanashi Prefecture, no significant differences in the quantities of Cry j1 between the upper and lower parts of the tree were observed in samples collected from March 1 to 14. Furthermore, the quantities of Cry j1 on March 1, 5, 10 and 14 were significantly lower than those on February 1. These results suggest that expression of C. japonica pollen levels in terms of particle numbers is not sufficient and that quantities of Cry j1 vary throughout the course of spring.