Therapeutic effects of Echinococcus granulosus cystic fluid on allergic airway inflammation

Previous studies showed that Echinococcus granulosus infection reduces allergic airway inflammation in experimentally infected hosts and the cystic fluid of E. granulosus is known to activate regulatory T (CD4 ⁺ CD25 ⁺ Foxp3 ⁺ T, Treg) cells. To evaluate the effects of cystic fluid of E. granulosus on allergic airway inflammation, we investigated the regulation of the inflammatory reaction by cystic fluid using an allergic airway inflammation animal model. Cystic fluid was administered to C57BL/6 mice seven times every other day, after which allergic airway inflammation was induced using ovalbumin and aluminum. The airway resistance, number of eosinophils and other immune cells in the bronchoalveolar lavage fluid, and levels of Th2 and Th17-related cytokines were significantly reduced by cystic fluid pre-treatment in allergic airway inflammation-induced mice. The number IL-4 ⁺ CD4 ⁺ T cells decreased, the number of Treg cells increased in the lung-draining lymph nodes and spleen of cystic fluid pre-treated mice. In conclusion, E. granulosus-derived cystic fluid may alleviate the Th2 allergic airway inflammatory response via Treg cells. Further studies of the immune regulation of cystic fluid may lead to the development of therapeutic agents for immune disorders.