Dual knock-down of ubiquitin (Ub) and autophagy-related gene (Atg) 7 decreased the ubiquitylation of phosphorylated IκBα (p-IκBα) and inflammatory responses in the murine alveolar macrophage cell line (MH-S). A, Interaction between p-IκBα and Ub is significantly decreased after Klebsiella pneumoniae infection after knock-down of both Ub and Atg7, compared with Atg7 small interfering RNA (siRNA)–silencing cells. Cells were transfected with Atg7 siRNA for 24 hours. At 24 hours after transfection, MH-S cells were transfected with Ub siRNA. After another 24 hours, the cells were infected by K. pneumoniae for 2 hours and then collected for the coimmunoprecipitation assay. B, Dual knock-down of Ub and Atg7 followed by K. pneumoniae infection decreased the expressions of tumor necrosis factor (TNF) α compared with the Atg7 siRNA group. After 24 hours, cells were infected with K. pneumoniae for 2 hours. Data were representative of 3 experiments. *P < .05 (1-way analysis of variance and Bonferroni selected multiple comparison test). Abbreviations: +, with; −, without; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; IB, immunoblotting; IP, immunoprecipitation.