Immunocytochemical localization of ecdysteroids in the life history stages of Schistosoma mansoni.

Sporocysts, cercariae and adults of S. mansoni exhibit focal immunoreactivity against anti-ecdysone serum in an indirect immunofluorescence assay. In adult males immunoreactivity is limited to cell bodies and linear connections in the parenchyma surrounding the intestinal caeca. In both unisexual and paired mature females part of the lining of the ootype is reactive, especially near the entrance of the vitelline duct; this demonstrates that females can make ecdysteroids without mal contact. Adult worms cultured completely in vitro show a similar pattern of reactivity. Immunoreactivity is strong in cercariae, but is essentially absent in miracidia.