title: TNF-alpha mediated modulation of T cell development and exacerbation of in vitro T1DM in fetal thymus organ culture.
abstract: TNF-alpha is a pleiotropic cytokine that is constitutively expressed in the thymus. This cytokine has opposing effects on type 1 diabetes mellitus (T1DM) as non-obese diabetic (NOD) mice administered TNF-alpha early in life experience an acceleration in disease onset while TNF-alpha administered to adult NOD mice are rescued from disease entirely. Using fetal thymus organ culture (FTOC) as a model of T cell development and an associated in vitro T1DM model, we set out to reconcile the role of TNF-alpha in thymic development with its role in the pathogenesis of T1DM. Our data indicate that NOD derived FTOC produce a smaller percentage of double negative (CD4(-)/CD8(-)) thymocytes expressing TNF receptors compared to non-diabetic C57BL/6 (B6) derived FTOC. NOD FTOC produce more TNF-alpha than B6 FTOC during days 6-9 of culture, a time when negative selection of T cells is known to occur. Neutralization of this endogenous TNF-alpha production in NOD derived FTOC with soluble TNF receptor (sTNF R1) rescued insulin production in our in vitro T1DM model. Flow cytometric analysis of NOD FTOC treated with recombinant TNF-alpha (rTNF-alpha) or sTNF R1 demonstrated that the relative levels of TNF-alpha in the culture during the selection window (days 6-9) influence the ratio of immature vs. mature T cells that emerge from FTOC.
authors: Department of Microbiology and Immunology, University of Arizona College of Medicine, Tucson, AZ 85274, USA. amiddlebrook@gladstone.ucsf.edu
authors: Aaron J
authors: AJ
authors: Middlebrook
authors: Ty
authors: T
authors: Lebsack
authors: Dominick
authors: D
authors: DeLuca
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000276:immunology / Q000378:metabolism; D016827:CD8 Antigens / Q000276:immunology / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000378:metabolism; D005333:Fetus; D007328:Insulin / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D009924:Organ Culture Techniques; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism / Q000494:pharmacology; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000196:embryology / Q000276:immunology* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens; D007328:Insulin; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D011994:Recombinant Proteins; C506236:Tnfrsf1a protein, mouse; D014409:Tumor Necrosis Factor-alpha