FIG 6.

Inhibition of Fn fibril formation increases the bacterial uptake in osteoblasts. Host cells were cultured for 2 days with a 70-kDa fragment of fibronectin to block Fn assembly. (A) Representative immunofluorescence microscopy images of Fn expression on pHOBs detected by anti-Fn antibody. (B) A549 cells and pHOBs cultured with the 70-kDa fragment of Fn as indicated and infected with S. aureus 6850 or S. carnosus TM300(pFnBA4) (MOI 50). One hour post infection, extracellular staphylococci were removed by lysostaphin treatment. Subsequently, the host cells were detached and the number of host cells was determined. Host cells were lysed and the number of viable intracellular bacteria was assessed by plate counting. Numbers of intracellular bacteria in non-pretreated cells were set to 100%. Data are means ± SD from 3 independent experiments. *, P < 0.05, one-way ANOVA followed by Dunnett’s multiple-comparison test.