Effect of granulocyte inhibitory factor on granuloma formation in mice infected with Schistosoma mansoni.

Mononuclear cells from patients infected with Schistosoma mansoni were able to produce a soluble material that inhibited the granulocyte cytotoxicity against schistosomula in a complement-dependent killing assay. This granulocyte inhibitory factor (GIF) appears to exist preformed in the mononuclear cells of patients, but it can also be released in the supernatant after antigenic stimulation (lymphokine-like). Only T lymphocytes were able to mediate the inhibition of granulocyte cytotoxicity against schistosomula in vitro. The treatment of S. mansoni-infected mice with GIF induced a significant decrease in the liver granuloma size.