MAJOR GRASS-POLLEN ALLERGEN LOL-P-1 BINDS TO DIESEL EXHAUST PARTICLES- IMPLICATIONS FOR ASTHMA AND AIR-POLLUTION

Background Grass pollen allergens are known to be present in the atmos phere in a range of particle sizes from whole pollen grains (approx. 2 0 to 55 mu m in diameter) to smaller size fractions < 2.5 mu m (fine p articles, PM(2.5)) These latter particles are within the respirable ra nge and include allergen-containing starch granules released from with in the grains into the atmosphere when grass pollen ruptures in rainfa ll and are associated with epidemics of thunderstorm asthma during the grass pollen season. The question arises whether grass can interact w ith other sources of fine particles, particularly those present during episodes of air pollution. Objective We propose the hypothesis that f ree grass pollen allergen molecules, derived from dead or burst grains and dispersed in microdroplets of water in aerosols, can bind to fine particles in polluted air. Methods We used diesel exhaust carbon part icles (DECP) derived from the exhaust of a stationary diesel engine, n atural highly purified Lol p 1, immunogold labelling with specific mon oclonal antibodies and a high voltage transmission electron-microscopi c imaging technique. Results DECP are visualized as small carbon spher es, each 30-60 nm in diameter, forming fractal aggregates about 1-2 mu m in diameter, Here we test our hypothesis and show by in vitro exper iments that the major grass pollen allergen, Lol p 1 binds to one defi ned class of line particles, DECP. Conclusion DECP are in the respirab le size range, can bind to the major grass pollen allergen Lol p 1 und er in vitro conditions and represent a possible mechanism by which all ergens can become concentrated in polluted air and thus trigger attack s of asthma.