Subpollen Particles from Ragweed Pollen Contain Allergenic Proteins and Oxidases

Sanjiv Sur, MD and Istvan Boldogh
University of Texas Medical Branch
P30ES006676

Fragments of pollen grains, called subpollen particles (SPPs), are capable of reaching the lower regions of the lung and cause clinical symptoms associated with seasonal asthma according to new research from NIEHS-supported researchers at the University of Texas Medical Branch in Galveston. How pollen allergens contribute to inflammation in the lower airways has been puzzling to researchers since all but a few pollen grains reach the peripheral airway due to their size.

The researchers found that ragweed pollen grains release SPPs in the range of 0.5 to 4.5 microns in size. They determined that the SPPs contained allergenic proteins and possessed NADH or NADPH oxidase activity. Exposure of cultured cells to SPPs caused significant increases in the generation of reactive oxygen species and induced allergenic airway inflammation in laboratory mice. Pretreatment of the SPPs with NADH and NADPH oxidase inhibitors reduced their ability to increase reactive oxygen species in the airway epithelial cells and subsequently reduced airway inflammation.

These findings represent the first report showing allergenic proteins and oxidase activity in SPPs of respirable size produced by plants. The oxidase activity and the allergenic proteins work together to cause the development of severe allergic inflammation. The study provides insight into the role of SPPs in seasonal asthma and suggests that inhibitors of SPP oxidases may be useful therapeutic agents in reducing or preventing oxidative damage and inflammation.

Citation: Bacsi A, Choudhury BK, Dharajiya N, Sur S, Boldogh I. Subpollen particles: carriers of allergenic proteins and oxidases. J Allergy Clin Immunol. 2006 Oct;118(4):844-50.