Comparative analysis of hepatic, pulmonary, and intestinal granuloma formation around freshly laid Schistosoma japonicum eggs in mice.

Hepatic, pulmonary, and intestinal granuloma formation was comparatively studied in mice implanted with freshly laid Schistosoma japonicum eggs. The liver and the lung showed similar kinetics of tissue reactivity, with the magnitude in the lung being of a significantly lower degree. When the footpad-swelling test was performed, the delayed-type hypersensitivity (DTH) response during hepatic granuloma formation was found to be significantly increased from the 28th day after egg implantation onward, whereas pulmonary granuloma formation showed a peak response at 14-21 days, suggesting differing kinetics of granulomatous reaction. In histologic analysis, the temporal infiltration of monocytes was revealed to correspond to the increase in the DTH response. During intestinal granuloma formation, eosinophil infiltration was the most marked feature. The present study demonstrates that throughout the course of reaction, cellular components participating in egg-granuloma formation differ greatly according to the tissues involved.