CNF1 potentiates LPS-triggered immune responses.

<p>(A) Monocytes (5x10⁵ cells per condition) isolated from mouse blood were treated with PBS (control) or with 1 μg/ml CNF1 toxin for 10 h with or without 100 ng/ml LPS. Cell culture supernatants were analyzed using mouse ELISArray kits (n = 3). The data are shown as fold inductions compared with the control condition. (B, C and D) Monocytes (5x10⁵ cells per condition) purified from mouse blood were treated for 10 h. Cells were treated as indicated with 0.1, 1, or 10 μg/ml of CNF1 toxin or the CNF1 mutant C866S alone or in combination with ultrapure <i>E</i>. <i>coli</i> LPS at 1, 10 or 100 ng/ml (n = 3). (B) KC, (C) IL-6, and (D) IL-1β cytokine secretion was analyzed using ELISA (n = 4). (E) Female BALB/c mice were intravenously infected with 10⁷ CFUs of <i>E</i>. <i>coli</i> expressing CNF1 (<i>E</i>. <i>coli</i>^CNF1+) + PBS as a control or with an <i>E</i>. <i>coli</i>^CNF1+ + IL-1β antagonist (Kineret; 1.5 mg/kg) prior to the collection of peripheral blood at 3, 6, 24 and 48 h for the measurement of bacteremia (n = 10). P-values <0.05 (*); and P-values <0.01 (**) were considered statistically significant.