Kinetic of NO2 uptake by Phleum pratense pollen: Chemical and allergenic implications.

Phleum pratense pollen was exposed to NO 2 in a reactor allowing a continuous analysis of NO 2 concentration by FTIR. The uptake coefficient of NO 2 on pollen was calculated postulating a first order kinetic reaction and a value of (1.1 ± 0.1) × 10 −7 was determined. NO 2 uptake was faster when the pollen water content was increased and when the pollen was pre-treated with ozone. The effect of NO 2 exposure on pollen allergic properties was investigated by quantifying Th2- and Th1-associated chemokines in a model of human dendritic cells. Cellular analysis clearly showed that cells exposed to fumigated pollen favored the production of chemokines known to promote Th2-cell responses. Altogether these data demonstrate that NO 2 uptake by pollen directly correlates with increased Th2 response in human cells, and are in favor of the involvement of NO 2 pollution in the increase of allergic diseases. [ABSTRACT FROM AUTHOR]