Induction of collagen synthesis in cultured human fibroblasts by live Schistosoma mansoni eggs and soluble egg antigens (SEA).

There is a dearth of knowledge on the tissue fibrosis that contributes to the pathology of schistosomiasis mansoni. The present study was designed to test the direct effect of live schistosome eggs and soluble egg antigens (SEA) on cultured normal human fibroblasts. Coincubation for 3 days of fibroblast monolayers with 100-500 live eggs/ml medium or equivalent amounts of SEA caused enhanced incorporation of labelled proline. The newly synthesized polypeptides were sensitive to purified collagenase enzyme activity. Collagen synthesis was also verified by measuring increased hydroxyproline content in fibroblasts. Whereas low numbers of eggs stimulated fibroblast activity, 500 eggs/ml medium caused a disarray in the arrangement of cells, with cytoplasmic granulation, cell detachment and death. These results indicate that fibroblast stimulation and collagen synthesis may also be triggered by the direct action of egg secretions on tissue fibroblasts.