title: Tumor necrosis factor enhances interferon-induced Ia antigen expression on murine islet parenchymal cells.
abstract: Islets from male B10.BR mice (H-2k) were isolated by the collagenase technique, hand-picked with a Pasteur pipette, and incubated in tissue culture media supplemented with recombinant murine interferon-gamma (rIFN-gamma), recombinant murine tumor necrosis factor (rTNF), or both. IAk-molecules could be identified on the surface of islets incubated for 5 days with a combination of rIFN-gamma (1, 10, or 100 ng/ml) and rTNF (10 or 50 U/ml) by indirect immunofluorescence. Optimal concentrations of rIFN-gamma and rTNF, 10 ng/ml and 50 U/ml, respectively, were used in all subsequent experiments. Weak Ia-positivity could be identified on the surface of islets cultured with both cytokines for as little as 48 hours; however, the staining appeared most intense after 5 days of culture. Intensely Ia-positive islets were then carefully washed and cultured in media without either cytokine; Ia positivity could be identified on the surface of these islets for up to 1 week. Dispersed islet cells were cultured with rIFN-gamma alone (10 ng/ml), rTNF alone (50 U/ml), or both cytokines for 5 or 10 days. After either 5 or 10 days of culture with both cytokines, intense immunofluorescent staining for Ia could be identified on the surface of greater than 80-90% of the viable islet cells. Culture with IFN alone for 10 days resulted in 15-20% Ia positivity; culture with TNF alone did not cause Ia expression.
mesh_terms: D000818:Animals; D005455:Fluorescent Antibody Technique; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis*; D007371:Interferon-gamma / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008297:Male; D051379:Mice; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D000949:Histocompatibility Antigens Class II; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma