Acanthamoeba profilin elicits allergic airway inflammation in mice

In previous studies, we suggested that Acanthamoeba is a new aero-allergen and that patients who showed positive results for the skin-prick test response to Acanthamoeba cross-reacted with several pollen allergens. Additionally, patients with common antibodies reacted to the 13-15 kDa Acanthamoeba unknown allergen. We examined whether profilin of Acanthamoeba is a human airway allergic agent because of its molecular weight. We expressed recombinant Ac-PF (rAc-PF) protein using an Escherichia coli expression system and evaluated whether Ac-PF is an airway allergic agent using an allergic airway inflammation animal model. Airway hyperresponsiveness was increased in rAc-PF-inoculated mice. The number of eosinophils and levels of Th2 cytokines, interleukin (IL)-4, IL-5, and IL-13 were increased in the bronchial alveolar lavage fluid of rAc-PF-treated mice. The lungs of the rAc-PF-treated mice group showed enhanced mucin production and metaplasia of lung epithelial cells and goblet cells. In this study, we demonstrated that rAc-PF may be an allergen in Acanthamoeba, but further studies needed to identify the mechanisms of allergenic reactions induced by Ac-PF.