Influence of Schistosoma japonicum infection on OVA -induced allergic reaction of mice

In order to study the influence of helminth infection on allergic asthma, 15 BALB/c mice were divided into three groups randomly. In group 1, mice were Schistosoma japonicum-infected and OVA-treated; in group 2, mice were treated with OVA only, and in group 3, mice without any treatment were taken as control. Firstly, the mice in group 1 were infected with Schistosoma japonicum; and then, from day 57 to day 84 after infection, mice in group 1 and group 2 were immunized and challenged with Ovalbumin(OVA) together to induce allergic asthma. On day 85, all the mice in three groups were killed, and spleens, lungs and bronchoalveolar lavage fluids(BALF) were collected. BALF smears were prepared for counting differential cells; lung tissue sections were prepared for examining pulmonary pathological changes, and splenocytes were cultured for measuring relevant cytokines in supernatants of the culture. Besides these, relevant cytokines in BALF were also detected. The results showed, compared with the mice in group 2, the eosinophils infiltrated in the lung of the mice in group 1 decreased dramatically(P0.05), and pulmonary inflammation diminished markedly(P0.05). Moreover, the levels of IL-4 and IL-5 in both BALF and supernatants of splenocyte culture reduced(P0.05), while the levels of IFN-γ did not change evidently(P0.05). All these results indicate that Schistosoma japonicum infection has inhibitory effect on OVA-induced allergic asthma.