BACKGROUND: Asthma incidence has long been linked to pollen, even though pollen grains are too large to penetrate into the airways where @entity748 responses originate. Pollen allergens found in small, respirable particles have been implicated in a number of @entity565 epidemics, particularly ones following rainfall or thunderstorms. OBJECTIVE: The aim of this study was to determine how pollen allergens form the respirable aerosols necessary for triggering @entity565 . METHODS: Flowering grasses were humidified and then dried in a controlled-environment chamber connected to a cascade impactor and an aerosol particle counter. Particles shed from the flowers were analyzed with high-resolution microscopy and immunolabeled with rabbit anti-Phl @entity3881 antibody, which is specific for group 1 pollen allergens. RESULTS: Contrary to what has been reported in other published accounts, most of the pollen in this investigation remained on the open anthers of wind pollinated plants unless disturbed-eg, by wind. Increasing humidity caused anthers to close. After a cycle of wetting and drying followed by wind disturbance, grasses flowering within a chamber produced an aerosol of particles that were collected in a cascade impactor. These particles consisted of fragmented pollen cytoplasm in the size range 0.12 to 4.67 microm; they were loaded with group 1 allergens. CONCLUSION: Here we provide the first direct observations of the release of grass pollen allergens as respirable aerosols. They can emanate directly from the flower after a moisture-drying cycle. This could explain @entity748 responses associated with grass pollination, particularly after moist weather conditions.

Release of allergens as respirable aerosols: A link between grass pollen and XXXX .

@entity748 :: ('MESH:D013224', 'Disease') :: ['asthmatic'] @entity565 :: ('MESH:D001249', 'Disease') :: ['asthma'] @entity3881 :: ('1423', 'Gene') :: ['p 1']
@entity565 :: (MESH:D001249,Disease) :: ['asthma']
