In a previous study, O157 was observed to adhere to RSE cells in vivo and in vitro, besides the FAE cells [5] and this observation was used to develop a unique in vitro adherence assay for O157 with RSE cells [5]. In this study, we decided to (i) evaluate if the LEE-encoded proteins would also be critical for O157 adherence to RSE cells, as for FAE cells, and (ii) in the event that these proteins would not play a significant role in RSE

cell adherence, define the find more proteome of O157 as expressed when grown in the adherence assay media, DMEM, to assemble targets for future evaluation in RSE adherence. Experimental and bioinformatic evaluation of such targets could in fact help identify a subset of novel adhesins that may have excellent potential to increase the efficacy of the anti-adhesion, cattle O157 vaccines, LY2874455 ic50 by eliminating O157 from both FAE and RSE cells at the RAJ. Methods Bacterial strains and culture conditions The wild-type O157 strain EDL933 (O157), a sequenced isolate

implicated in human disease [21], was used in this study. We cultured O157 in Dulbecco Modified Eagle Medium-Low Glucose (DMEM; Gibco/lnvitrogen Corporation, Grand Island, NY), for the cell adherence assays described below. The rationale for the use of this culture medium was (i) to reflect the growth conditions used in the eukaryotic cell adherence assays; and (ii) to closely parallel the in vivo nutrient-limiting conditions, and conditions used to prepare the cattle-use approved, LEE protein based, anti-adhesion O157 vaccine. In addition, Geneticin manufacturer another wild-type O157 strain 86–24 (86–24), its isogenic mutant (86-24eae Δ10) negative for Intimin, and this mutant complemented with the plasmid pEB310 (86-24eae Δ10(pEB310)) expressing Intimin, were also tested in the adherence assay [22]. The 86–24 strain and its derivatives were obtained from Dr. A. D. O’Brien, Uniformed Services University of the Health Sciences, Bethesda, MD. We also cultured O157 in DMEM for proteomic analysis. Specifically, an overnight culture of the wild-type O157 strain in Luria-Bertani

(LB) broth was pelleted PDK4 and washed with sterile phosphate buffered saline (PBS; pH 7.4), and subcultured to an initial OD600 of 0.05 in fresh DMEM. After incubation at 37 °C with shaking at 250 rpm to an OD600 of 0.8 to 1.0, cells were harvested by centrifugation at 7,000 rpm, 15 min at 4 °C. Cells were washed three times with an equal volume of sterile PBS (pH 7.4), and processed to obtain cell lysate and pellet fractions for proteomic analysis as previously described [23]. O157-RSE cell adherence inhibition assay: (i) in the presence of pooled anti-LEE proteins, anti-intimin and anti-H7 antisera Adherence of O157 to the RSE cells was previously demonstrated and developed into an adherence assay in our laboratory [5].