title: Cytotoxic effects in vitro of human monocytes and macrophages on schistosomula of Schistosoma mansoni.
abstract: Human peripheral blood monocytes from normal donors were isolated by differential centrifugation and cultured in vitro in hydrophobic Teflon-coated tissue culture bags. Cells were harvested between 0 and 10 days and tested for their ability to kill schistosomula of Schistosoma mansoni in an in-vitro cytotoxicity assay. Freshly isolated, unstimulated monocytes demonstrated minimal cytotoxic capability. However, this was increased if the cells were pretreated with human recombinant gamma interferon (IFN-gamma), or with specific anti-S. mansoni antiserum. As the monocytes matured in vitro there were marked increases in the levels of antibody-independent killing of schistosomula. Monocytes grown in vitro with IFN-gamma (10(4) u/ml) took 2-3 days to develop almost maximal cytotoxicity (mean 94% kill of schistosomula). In contrast, unstimulated monocytes (no IFN-gamma) took between 5 and 7 days to achieve comparable cytotoxicity (mean 99% kill). Killing of the schistosomula was dependent upon a high effector to target ratio, and was a relatively slow phenomenon in vitro, parasite attrition occurring between 17 and 36 h. Supernatants from cytotoxic macrophages were ineffective in mediating cytotoxicity of the parasite.
authors.affiliation: Department of Pathology, University of Cambridge, UK.
authors.forename: B
authors.initials: B
authors.lastname: Cottrell
authors.forename: C
authors.initials: C
authors.lastname: Pye
authors.forename: A
authors.initials: A
authors.lastname: Butterworth
mesh_terms: D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000008:administration & dosage; D000920:Antibody-Dependent Cell Cytotoxicity; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology*; D008297:Male; D009000:Monocytes / Q000276:immunology*; D012550:Schistosoma mansoni / Q000254:growth & development / Q000276:immunology*; D013997:Time Factors
chemical_list: D000909:Antibodies, Helminth; D007371:Interferon-gamma