Differential allergenicity of mature and immature pollen grains in Shasta daisy (Chrysanthemum maximum Ramond).

Weed pollen grains belonging to the Asteraceae family contain a variety of allergens inducing type I and IV allergies in susceptible people. The aim of this research was to compare the allergenic properties of immature and mature Shasta daisy pollen grains (Chrysanthemum maximum Ramond) to define the potential role of the maturation process on the allergenicity of Asteraceae pollen grains. The immature (IP) and mature pollen (MP) grains were first studied by optical and scanning electron microscopand their protein contents were quantitatively and qualitatively analyzed. Pollen extracts were finally used to sensitize guinea pigs in order to obtain IP and MP specific antibodies. Nasal provocation tests using IP and MP crude extracts were also performed on pre-sensitized guinea pigs. The MP extract induced IgE and eosinophilia in blood and positive skin tests in sensitized guinea pigs. Moreover, high number of eosinophils was found in the nasal mucosa of MP sensitized guinea pigs. SDS-PAGE analysis of the IP and MP protein content showed seven and five apparent bands ranging from 7 to 66kDa respectively. According to immunoblot analysis, MP extract contained a single allergen of 66kDa. The overall results showed developmental processes of Shasta daisy pollen grains towards both morphological and molecular changes increasing their allergenic potency.