A comparative study on the allergenicity, structure, and ultrastructure of two Acacia pollen grains in guinea pigs

Abstract

Acacia saligna and Acacia victoria are native to Australia brought to and grown in Southern Iran. They have since had a widespread distribution and become native in Iran. As people of the region are exposed to the pollen grains from these plants during a 5 months period, this study aimed at investigating the allergenicity of their mature pollen grains. In addition, the structural and ultrastructural as well as the total protein content of the mature pollen grains were analyzed. Pollen grains of A. saligna and A. victoria were collected from the suburbs of Ahvaz, Iran. Pollen extracts (15 % concentration) were prepared in PBS (pH 7.2), and 4- to 6-week-old male guinea pigs (Hartly) were used for allergenicity tests. Skin tests showed a significant increase in flare diameter. Clinical tests also showed a significant change in the levels of eosinophils, neutrophils, and IgE. Comparative analysis of the allergenicity of A. saligna and A. victoria pollen grains revealed a higher IgE level in the latter. Comparative analysis of pollen characteristics was performed using both light and electron microscopy for sporoderm structure and ultrastructure, respectively. Twelve percent PAGE analysis of the total protein content of mature pollen grains showed a greater number of bands in A. victoria, while four bands were common in both species. In conclusion, this study demonstrates that both A. saligna and A. victoria pollen grains are allergenic, with a greater allergenicity of A. victoria pollen grains. In addition, the structural and ultrastructural as well as the total protein content of the mature pollen grains are revealed, and a potential protein allergen is proposed.