In this study, we used computer software and protein network servers to analyze the physical Selleckchem IBET762 and chemical properties, secondary structure and antigenicity of IntC300 in order to search for a novel synthetic peptide vaccine candidate against EHEC O157:H7. We performed a comprehensive analysis of all kinds of parameters

to predict B-cell epitopes, designed a peptide, coupled it with KLH, immunized animals and measured antibody titers. We infected the mice with viable EHEC O157:H7 to explore the immune protection conferred by a synthetic peptide epitope against EHEC O157:H7. We hope to find a novel synthetic peptide vaccine candidate against EHEC O157:H7. The amino acid sequence of intimin (GenBank Accession no: CAA77642, 934 aa) from EHEC O157:H7 strain EDL933 was obtained from GenBank and the 300 amino acids (635–934) Pirfenidone mouse at the C-terminus of intimin were chosen as the target for analysis. Its hydrophilic index (Hopp-Woods method) (14), β-turn (Chou-Fasman method) (15), flexibility

(Karplus-Schulz method) (16), accessibility (Emini method) (17) and antigenicity (Jameson-Wolf method) (18) were analyzed. The B-cell epitopes of IntC300 were predicted using the method of Kolaskar-Tongaonakar from the protein network server at Harvard University (http://bio.dfci.harvard.edu/Tools/antigenic.pl) (19). After a comparative analysis, a short peptide with consistent parameters in all predictions was chosen as the candidate for B-cell epitope of IntC300. Among the five

predicted antigen peptides, KT-12 (KASITEIKADKT) Nitroxoline met the best antigen parameters and was therefore chosen to be synthesized by Shenzhen Hybio Engineering Shenzhen, China. The parameters for this synthetic peptide were as follows: purity >94.1%, molecular weight 1304.5 and weight 10.8 mg. Ten milligrams of KLH (Sigma, St Louis, MO, USA) was taken and fully dissolved in 1 mL of pH 10 borate buffer, after which 1 μmol of synthetic peptide KT-12 was added. Next 1 mL freshly prepared 0.3% glutaraldehyde solution was added while the solution was shaking at room temperature and the resulting mixture left to react for 2 hr (solution turned yellow). Upon completion of the reaction, the tube was inverted several times, then 0.25 mL 1 M glycerol was added and the mixture incubated for 30 min to block unreacted glutaraldehyde. The sample was dialyzed against 2 L pH 8.5 borate buffer overnight (4°C), the buffer changed and dialysis continued for 4 hr, and the final product packaged and stored at −20°C for future use. The same method was used to prepare the conjugate of BSA (Sigma) with KT-12 for ELISA.