title: Activation-induced cell death in human peripheral blood lymphocytes after stimulation with silicate in vitro.
abstract: Silica and related substances such as silicate have been proven to possess "adjuvant effects". We have previously reported a finding of polyclonal human T cell activation induced by silicate as a superantigen in vitro. In this study, we observed activation-induced cell death in human lymphocytes after stimulation with chrysotile, a kind of silicate. Apoptotic cells were detected flow cytometrically using the TUNEL assay, and the maximum appearance of TUNEL positive cells occurred on day 4 of incubation. Simultaneously the manifestation of small-sized cells in the specimens increased implying apoptosis. Fas expression on lymphocytes increased to day 3 of incubation with chrysotile, and then spontaneously decreased on day 4 when remarkable apoptosis could be detected. Based on these results it is conceivable that activation-induced cell death occurred through Fas-Fas ligand interaction in lymphocytes after stimulation with silicate in a concentration with which no acute cytotoxicity has been detected. Whether and how the repeated apoptosis in definite clones of lymphocytes causes the induction of sFas synthesis need clarification.
authors.affiliation: Department of Hygiene, Kawasaki Medical School, Kurashiki 701-01, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Aikoh
authors.forename: A
authors.initials: A
authors.lastname: Tomokuni
authors.forename: T
authors.initials: T
authors.lastname: Matsukii
authors.forename: F
authors.initials: F
authors.lastname: Hyodoh
authors.forename: H
authors.initials: H
authors.lastname: Ueki
authors.forename: T
authors.initials: T
authors.lastname: Otsuki
authors.forename: A
authors.initials: A
authors.lastname: Ueki
mesh_terms: D017632:Asbestos, Serpentine / Q000494:pharmacology; D017252:CD3 Complex / Q000096:biosynthesis / Q000187:drug effects; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000502:physiology; D002273:Carcinogens / Q000008:administration & dosage / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D053222:Fas Ligand Protein; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis / Q000187:drug effects; D008213:Lymphocyte Activation / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000187:drug effects; D017640:Silicates / Q000008:administration & dosage / Q000276:immunology / Q000494:pharmacology*; D018089:Superantigens / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000502:physiology
chemical_list: D017632:Asbestos, Serpentine; D017252:CD3 Complex; D002273:Carcinogens; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D018950:Lipopolysaccharide Receptors; D008562:Membrane Glycoproteins; D017640:Silicates; D018089:Superantigens