Evaluation of vitronectin-mediated adherence of Mx strains expressing CEACAM-binding UspA2 variant proteins to A549 human lung epithelial cells.

<p>A549 cells were pretreated with IFN-γ for 24 h prior to infection to mimic epithelial inflammation. Cells were infected with 035E Hag-, Hag- derivative of 035E D2 and clinical isolates MX1, S36:1 and S43:4 at an MOI of 100 for 1 hr at RT. Infections were performed in medium 199 in the absence of serum but in the presence of A0115 to inhibit CEACAM-mediated interactions (see right column <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045452#pone-0045452-g008" target="_blank">Figure 8</a> for binding in the absence of A0115). In addition, media contained from the left, native vitronectin (nVn; column 1), activated vitronectin (aVn; column 2), aVn and RGDS (column 3) and aVn and RGES (column 4). Following infection, fixed monolayers were treated as described in the legend to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0045452#pone-0045452-g008" target="_blank">Figure 8</a>. Higher levels of Mx binding in the presence of aVn compared to nVn could be seen in all cases. In addition, a reduction of aVn-mediated Mx binding to A549 cells was observed in the presence of RGDS but not the control tetrapeptide RGES. Data are representative of duplicate infections performed on at least two separate occasions. Scale bar is 20 µm.