title: Cytotoxic effects of cytokines on human pancreatic islet cells in monolayer culture.
abstract: Interleukin-1 (IL-1), tumor necrosis factor (TNF), and interferon-gamma (IFN gamma) inhibit insulin release and may be cytotoxic to isolated rodent pancreatic islets. In this study we examined the effects of IL-1, TNF, and IFN gamma on the viability and hormone secretion of islets isolated from adult human pancreas and maintained in monolayer culture. IL-1 and TNF were cytotoxic to the islet cells (20-30% cell lysis) in a 51Cr release cytotoxicity assay, and IFN gamma had only small effects (less than 10% lysis). Combination of maximally cytotoxic concentrations of IL-1 (10 U/mL) and TNF (10(3) U/mL) produced an additive cytotoxic effect. IFN gamma (10(3) U/mL) acted synergistically with IL-1 and TNF, and the three cytokines added together produced maximal islet cell lysis (46.4 +/- 4.3%). Assay of insulin and glucagon in the islet monolayers revealed that IL-1, TNF, and IFN gamma inhibited both B- and A-cell secretory functions; however, only IL-1 and TNF produced permanent decreases in insulin and glucagon contents in the islet cultures. These findings indicate that IL-1 and TNF, as single agents, are cytotoxic to human islet cells, and that this cytotoxicity can be amplified by combining the cytokines and/or adding IFN gamma. However, the lack of specificity for B-cells in vitro suggests that additional factors might be operative in vivo for the cytokine products of macrophages and lymphocytes infiltrating islets to produce the B-cell-specific damage characteristic of type 1 diabetes.
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Rabinovitch
authors.forename: W
authors.initials: W
authors.lastname: Sumoski
authors.forename: R V
authors.initials: RV
authors.lastname: Rajotte
authors.forename: G L
authors.initials: GL
authors.lastname: Warnock
mesh_terms: D000328:Adult; D001685:Biological Factors / Q000494:pharmacology*; D002478:Cells, Cultured; D016207:Cytokines; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005934:Glucagon / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D012636:Secretory Rate / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D001685:Biological Factors; D016207:Cytokines; D007328:Insulin; D007375:Interleukin-1; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D005934:Glucagon