Figure 2

CiaD is required for the maximal secretion of interleukin-8 from host cells. A) Schematic representation of the CiaD Mitogen-activated protein kinase docking (MKD) motif residues 137–147 and the proline-directed phosphorylation site ((S/T)P) motif residue 54. (B) CiaD is required for the maximal secretion of IL-8 by INT 407 cells. The flgBC flagellar mutant was included as a negative control. The values obtained from uninfected cells were subtracted from all other values. The asterisks indicate a significant reduction in the amount of IL-8 detected in the supernatants compared to the value obtained using the C. jejuni wild-type strain, using a one-way ANOVA followed by post-hoc Tukey’s analysis (P < 0.05). Error bars represent ± SEM of N = 12 samples from 3 independent experiments. (C) CiaD is secreted from a C. jejuni ciaD mutant transformed with pRY111 vector harboring the CiaD-FLAG-tagged protein. Blots were probed with FLAG and CysM antibodies. Also included was a C. jejuni ciaD mutant without the pRY111 shuttle vector (-) as a negative control. (D) The C. jejuni ciaD mutant is motile. Motility assays were performed as outlined in Methods. (E) Deletion of ciaD does not have an effect on C. jejuni binding to host cells at 30 min post-infection.