title: Murine T-cell clones against Entamoeba histolytica: in vivo and in vitro characterization.
abstract: Eleven T-cell clones were raised from the spleens of BALB/c mice hyperimmunized against a crude soluble extract of Entamoeba histolytica trophozoites. Seven clones were of the Lyt-1+, and four of the Lyt-23+ phenotype. All clones proliferated in the presence of E. histolytica antigens but not to a purified protein derivative; five clones proliferated to a crude extract of the E. histolytica-like Laredo amoebae. Ten clones secreted T-cell growth factors in response to E. histolytica antigens. Two clones (Lyt-23+) mediated direct lymphocytotoxicity (73% and 86%) against amoebic trophozoites that was inhibited with rabbit anti-mouse TNF-alpha. Supernatants of five of the clones (all Lyt-1+) activated mouse peritoneal macrophages (Mphi) to kill E. histolytica trophozoites in vitro, seemingly independent of secreted reactive oxygen intermediates (O2- and H2O2) in the case of three clones supernatants. All of the clones that were activating Mphi to kill amoeba in vitro also mediated a local DTH reaction in mouse footpad. Our results demonstrate direct lymphocyte cytotoxicity via a cytolytic molecule antigenically related to TNF-alpha and lymphokines activating Mphi for amoebic killing by oxidative and non-oxidative mechanisms, the latter process mediated by a macrophage-activating factor (MAF) distinct from interferon-gamma (IFN-gamma).
authors.affiliation: Institute of Parasitology of McGill University, Macdonald College, 21,111 Lakeshore Road, Ste-Anne de Bellevue, Québec, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Denis
authors.forename: K
authors.initials: K
authors.lastname: Chadee
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000494:pharmacology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D002999:Clone Cells; D004748:Entamoeba histolytica / Q000276:immunology*; D005260:Female; D006133:Growth Substances / Q000378:metabolism; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007114:Immunization; D016130:Immunophenotyping; D007376:Interleukin-2 / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D013481:Superoxides / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: D000953:Antigens, Protozoan; D006133:Growth Substances; D007376:Interleukin-2; D013481:Superoxides