3.1. Effect of oral MQL administration on OVA-induced allergy
In this study, we examined whether oral administration of MQL affects Th2-related allergic immune responses using an OVA-induced mouse model of allergy. The mice were sensitized and immunized by OVA and orally administered MQL for 2 weeks. We investigated typical allergic responses such as production of IgE and Th2-mediated cytokines including IL-4, IL-5, and IL-13. We found that levels of serum IgE and splenic Th2 cytokines were significantly suppressed by oral administration of MQL(Fig. 1B-E) .
In our previous study, we showed that Rosae multiflorae fructus extract containing MQL suppressed Th2-related immune responses by inhibiting the proliferation of immune cells via up-regulation of HO-1 expression. Similarly, it has been reported that increased HO-1 expression in CD4+ T cells suppressed proliferation by inhibiting IL-2 production7. Based on these studies, we measured IL-2 production and proliferation of splenocytes, and confirmed that these were significantly reduced in MQL-administered groups (Fig. 1F and 1G) . Furthermore, we found that splenocytes in MQL-administered groups had increased HO-1 expression compared to the sham group (Fig. 1H) .