Evaluation of IFNγ+TNFα synergy and intracellular pathways involved in CXCL10 secretion by Hfsmc.

A, CXCL10 secretion, virtually absent in control, was significantly increased by 24γ (1000 U/ml) and TNFα (10 ng/ml) and enhanced at the highest level only by their combination; *P<0.05 or **P<0.01 vs. control; °°P<0.01 vs. each other cytokines, single or combined. IL-12 (50 ng/ml), IL-18 (50 ng/ml), IL-2 (25 U/ml) and IL-4 (20 ng/ml) had effect onto neither IFNγ- nor TNFα-induced CXCL10 secretion, except for IL-18 combined with TNFα (°P<0.05 vs. TNFα-induced secretion). Data are expressed as pg/µg protein, mean±S.E. Results are obtained from six experiments with different cell preparations. B, IFNγ+TNFα-induced CXCL10 secretion was significantly reduced by the blockade of different intracellular pathways with the specific inhibitors: fludarabine (Stat-1) 66.08±6.05%; LY294002 (PI3K) 77.6±10.97%; SB 203580 (p38 MAPK) 91.70±12.86%; U0126 (ERK1/2) 60.70±6.88%; BAY 11–7082 (NF-kB) 39.40±12.71%; SP600125 (JNK) 17.84±10.10%. *P<0.05 vs. IFNγ+TNFα-induced secretion, taken as 100%; #P<0.05 vs. all other treatments except for BAY 11–7082; §P<0.05 vs. SB 203580. Results (mean±S.E.) are expressed as % of IFNγ+TNFα-induced CXCL10 secretion (taken as 100%). Data are obtained from five experiments with different cell preparations.