Effects of Cercarial Extracts of Schistosoma mansoni on HeLa Cells

Abstract

FOR many years investigators have suggested that parasite toxins play a part in the pathology of schistosomiasis^1–3. Unfortunately, no attempts seem to have been made to evaluate the cytotoxic potential of schistosomes in vitro until recently. In 1936 and 1937 cercarial extracts of the trematodes Diplostomum flexicaudum and Cryptocotyle lingua were reported to produce cytopathology in excised tissue from lower vertebrates^4,5. Not until 1965, however, was there any report of the toxic effects of schistosomes on mammalian cells in culture⁶. It is now suggested that abnormal changes occur in monkey heart cell cultures to which viable eggs or egg extracts of Schistosoma mansoni have been added. Some of the effects include: breakdown of the monolayer growth pattern, loss of selective permeability against eosin Y, and metabolic inhibition (that is, no drop in pH.) of treated cultures.