Figure 1

Cigarette smoke extract decreases type II interferon-induced protein expression. A: ICAM-1 cell surface protein levels were determined using an enzyme-linked immunoassay with hTBE cell monolayers that were first treated with media without or with CSE at the indicated concentration for 4 hours. Cells were then incubated for 20 hours in media containing the same CSE concentration without or with IFN-γ. Values are expressed as mean ± S.D. (n = 3 replicates), and a significant difference (p < 0.05) in IFN-γ-induced levels between cells treated versus not treated with CSE is indicated by an asterisk. B: IRF-9, ICAM-1, HSP90, and β-actin protein levels were assessed using immunoblot analysis of extracts from hTBE cells that were first treated with media without or with CSE at the indicated concentration for 4 hours, followed by incubation for 8 hours in media containing the same CSE concentration without or with IFN-γ. C: Total Stat1 and β-actin protein levels were assessed using immunoblot analysis of extracts from hTBE cells that were first treated with media without or with CSE at the indicated concentration for 4 hours, followed by incubation for 8 hours in media containing the same CSE concentration without or with IFN-γ. In B and C, protein levels were quantified using band densitometry of immunoblot analyses from separate experiments with the value for cells not exposed to CSE but treated with IFN-γ set at 1 in each experiment. Values are expressed as mean ± S.D. (n = 4 experiments) in the bar graph adjacent to a representative immunoblot analysis, and a significant difference (p < 0.05) in IFN-γ-induced levels between cells treated versus not treated with CSE is indicated by an asterisk.