METHODS: Eosinophils were isolated from the blood of healthy volunteers and subsequently stimulated with either Japanese cedar pollen (crude) or Cryj1 (the major Japanese cedar pollen allergens), and their adhesion to recombinant human intercellular cell adhesion molecule (rh-ICAM)-1 was measured using eosinophil peroxidase assays. The generation of eosinophil superoxide anion (O2⁻) was examined based on the superoxide dismutase-inhibitable reduction of cytochrome C.
RESULTS: Both the crude extract of Japanese cedar pollen and Cryj1 directly enhanced the adhesion of eosinophils to ICAM-1 (N=6 each, both P<0.01). Furthermore, the crude Japanese cedar pollen extract and Cryj1 also significantly induced eosinophil O2⁻generation (N=6 each, both P<0.01).
CONCLUSIONS: These findings suggested that Japanese cedar or Cryj1 directly up-regulates eosinophil functions such as O2− generation and cell adhesion. These effects may be involved in the activation of eosinophils and could possibly aggravate the airway diseases associated with Japaneses cedar pollinosis.