Variable expression of pathogenesis-related protein allergen in mountain cedar (Juniperus ashei) pollen

Allergic diseases have been increasing in industrialized countries. The env ironment is thought to have both direct and indirect modulatory effects on disease pathogenesis, including alterating on the allergenicity of pollens. Certain plant proteins known as pathogenesis-related proteins appear to be up-regulated by certain environmental conditions, including pollutants, an d some have emerged as important allergens. Thus, the prospect of environme ntally regulated expression of plant-derived allergens becomes yet another potential environmental influence on allergic disease. We have identified a novel pathogenesis-related protein allergen, Jun a 3, from mountain cedar (Juniperus ashei) pollen. The serum IgE from patients with hypersensitivity to either mountain cedar or Japanese cedar were shown to bind to native an d recombinant Jun a 3 in Western blot analysis and ELISA, Jun a 3 is homolo gous to members of the thaumatin-like pathogenesis-related (PR-5) plant pro tein family. The amounts of Jun a 3 extracted from mountain cedar pollen va ried up to 5-fold in lots of pollen collected from the same region in diffe rent years and between different regions during the same year. Thus, Jun a 3 may contribute not only to the overall allergenicity of mountain cedar po llen, but variable levels of Jun a 3 may alter the allergenic potency of po llens produced under different environmental conditions.