Systemic and mucosal pre-administration of recombinant Helicobacter pylori neutrophil-activating protein prevents ovalbumin-induced allergic asthma in mice

Purpose: Previous epidemiologic studies have demonstrated an inverse association between Helicobacter pylori infection and the frequency of allergic asthma. The neutrophil-activating protein (NAP) of H. pylori has been identified as a modulator possessing anti-Th2 inflammation activity. Here, we sought to determine whether systemic or mucosal pre-administration of recombinant H. pylori NAP (rNAP) could prevent ovalbumin (OVA)-induced allergic asthma in mice. Methods: Mice were exposed to purified rNAP through intraperitoneal injection or inhalation and then sensitized with OVA. Following a challenge with aerosolized OVA, the bronchoalveolar lavage fluid (BALF) cell count, lung tissue histology, BALF cytokines and serum IgE were evaluated. Results: Both intraperitoneal injection and inhalation of rNAP prior to OVA sensitization significantly reduced eosinophil accumulation and inflammatory infiltration in lung tissue in OVA-induced asthma mice; eosinophils were reduced in the BALF of rNAP-treated mice. In addition, IL-4 and IL-13 levels were lower (P < 0.01), IL-10 and IFN-gamma levels were higher (P < 0.01) and IgE serum levels were lower (P < 0.01) in the treated groups compared to the control group. Conclusions: Systemic and mucosal pre-administration of rNAP could suppress the development of OVA-induced asthma in mice; rNAP may be utilized as part of novel strategies for the prevention or treatment of allergic diseases.