FIGURE 1.

Acinetobacter baumannii secretes pro-inflammatory factors. (A) THP1-XBlue reporter cells infected with A. baumannii (Ab19606 and Ab17978) at MOI 10. Levels of secreted embryonic alkaline phosphatase (SEAP) were assessed after 24 h of infection. The experiments were done in triplicates. Error bars represent standard deviation. One-way ANOVA with Tukey’s multiple comparisons test. (B) THP1-XBlue reporter cells treated with culture filtrates from A. baumannii (Ab19606 and Ab17978). TSB medium was used to grow the bacterial cultures and fresh TSB medium treatment served as the negative control. Levels of SEAP were assessed after 24 h from the beginning of the treatment. The experiments were done in triplicates. Error bars represent standard deviation. One-way ANOVA with Tukey’s multiple comparisons test. (C) THP1-XBlue reporter cells treated with culture filtrates from the indicated clinical isolates of A. baumannii. TSB medium was used to grow the bacterial cultures and fresh TSB medium treatment served as the negative control. Levels of SEAP were assessed after 24 h from the beginning of the treatment. The experiments were done in triplicates. Error bars represent standard deviation. One-way ANOVA with Tukey’s multiple comparisons test. (D) Western blot to check the phosphorylation of NF-κB p65 in RAW264.7 macrophages after the indicated infection (at MOI 10) or culture filtrate treatment. (E) THP1-XBlue reporter cells treated with different dilutions of the culture filtrate from A. baumannii (Ab19606). 10-fold serial dilutions of the culture filtrate were done in fresh TSB medium. Levels of SEAP were assessed after 24 h from the beginning of the treatment. The experiments were done in triplicates. Error bars represent standard deviation. All the experiments were performed three times independently. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.