Autotransplantation of hepatic granulomas into the skin of mice with Schistosoma mansoni infection

Abstract

Hepatic egg granulomas of mice infected with Schistosoma mansoni were transplanted into the skin of the same animal and changes occurring to macrophages, eosinophils, and mast cells over time were studied by light and electron microscopy and by autoradiographic techniques. Disappearance of cellular components about the egg granulomas occurred within 1 week; the entire implant became encapsulated by inflammatory cells and stroma. By 3 weeks mononuclear cells and macrophages reorganized the granulomas around the eggs and neutrophils disappeared. Activated macrophages contained both secretory rough endoplasmic reticulum and lysosomal-dense bodies. Granuloma size increased up to 5 weeks after implantation and mast cells and eosinophils tended to migrate into the granulomas. The mast cell index always remained lower than in the original hepatic granulomas, while eosinophils were seen in large numbers. During 3 to 8 weeks after implantation mononuclear cells undergoing DNA synthesis in the granulomas ranged from 2.9-4.8%. Some 3-week-old autotransplants were injected with 3H-thymidine and biopsied from 1 to 21 days later. Labeled mononuclear cells peaked in the granulomas by 10 days (24%) and the numbers fell off sharply after that. These findings indicate that autologously implanted schistosome egg granulomas can be maintained successfully in the skin for prolonged periods with marked ingress of macrophages and eosinophils. The autoradiographic data suggest the lesions are high turnover granulomas.