Abstract
BACKGROUND: Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) and Proteus mirabilis are the most important pathogens causing UTIs. The FimH from type 1 pili of UPEC and the MrpH from P. mirabilis play critical roles in the UTI process and have presented as ideal vaccine candidates against UTIs. There is no effective vaccine against UTI and the development of an ideal UTI vaccine is required. MATERIALS AND METHODS: In this study, we planned to design a novel fusion protein of FimH from UPEC and MrpH from P. mirabilis. For this purpose, we modeled fusion protein forms computationally using the Iterative Threading Assembly Refinement (I-TASSER) server and evaluated their interactions with toll-like receptor 4 (TLR4). The best fusion protein was constructed using overlap extension polymerase chain reaction (OE-PCR) and the biological activity of fusion was evaluated by the induction of interleukin-8 (IL-8) in the HT-29 cell line. RESULTS: Our study indicated that based on the Protein Structure Analysis (ProSA)-web and the docking results, MrpH.FimH showed better results than did FimH.MrpH, and it was selected for construction. The results of bioassay on the HT-29 showed that FimH and MrpH.FimH induced significantly higher IL-8 responses than untreated cells or MrpH alone in the cell line tested. CONCLUSIONS: In the present study, we designed and constructed the novel fusion protein MrpH.FimH from UPEC and P. mirabilis based on in silico methods. Our bioassay results indicate that the MrpH.FimH fusion protein is active and capable of inducing immune responses.