M13-RGD8 is efficiently internalized by HeLa cells prior to or during infection with Ct. (A) Infection of HeLa cells with Ct reference strain L2 at an MOI of one; (B) Infection of HeLa cells with M13-RGD8 at a concentration of 109 pfu/mL; (C) Pre-treatment of HeLa cells with M13-RGD8 for 2 h prior to Ct infection using the same MOI and pfu as in A and B, respectively; and (D) Co-treatment of HeLa cells with M13-RGD8 and Ct. (D, Inset) Ct inclusion surrounded by M13-RGD8. Blue, DAPI (nuclei); Green, M13-RGD8; Red, Ct (red, magenta). 40x; inset, 100x. (E) Quantitated titers of M13-RGD8 uptake (y-axis, left) and quantitated Ct IFU (y-axis, right) at 36 h post infection show dramatically increased phage and Ct viability. Data represent three independent experiments.