Objective: To investigate the effect of antigens of different stage Schistosoma japonicum on airway inflammation in a murine model of asthma.
Methods: 48 female BALB/c mice were randomly divided into eight groups. Mice in group A were given normal saline of equal volume as control. Group B was asthma model which was established by intraperitoneal and intranasal challenge with OVA. Mice in groups C, D and E were immunized with soluble egg antigen (SEA), soluble male worm antigen (SWA), and schistosomulum antigen (SSA) respectively 4 times in a week interval, followed by OVA sensitization as in group B 1 week after the final immunization. Mice in groups F, G, and H were immunized with SEA, SWA, and SSA respectively but sensitized and challenged with saline instead of OVA. 48 hours after asthma was induced, the mice were sacrificed. Leukocytes and eosinophils were counted in bronchoalveolar lavage fluid (BALF). The level of IL-5, IL-10 and IFN-gamma in BALF was detected. Pathologic changes in lung tissues were observed.
Results: Inflammation cells, especially eosinophils, appeared in airways of mice in groups B, C, D and E, but with much less number in groups C, D and E. No inflammation cells were seen in airways of group A mice. The number of leukocytes, eosinophils and level of IL-5 in BALF of group B [(98.4 +/- 16.1) x 10(4)/ml, (17.6 +/- 4.3) x 10(4)/ml, (197.9 +/- 36.5) pg/ml respectively] were significantly higher than those of group A [(8.2 +/- 1.1) x 10(4)/ml, (0.02 +/- 0.01) x 10(4)/ ml, (12.3 +/- 7.4) pg/ml], however the levels of IL-10 and IFN-gamma were significantly lower than that of group A (P < 0.05). The number of leukocytes, especially eosinophils, in BALF of groups C, D and E was significantly lower than that of group B. The level of IL-5 in BALF of groups C, D and E was significantly reduced, while that of IL-10 and IFN-gamma in BALF of the 3 groups was significantly higher than group B (P < 0.05).
Conclusions: The immunization with S. japonicum antigens can effectively modulate the level of cytokines and inhibit the eosinophil infiltration and airway inflammation in asthmatic mice.