Abstract
Helicobacter pylori neutrophil-activating protein (HP-NAP) is an important virulence factor of Helicobacter pylori (H. pylori) for pathogenesis. To investigate how HP-NAP activates human neutrophils, HP-NAP was expressed in Escherichia coli (E. coli) and purified by the two sequential gel filtration chromatographies. The molecular weight of HP-NAP monomer was confirmed by liquid chromatography/mass spectrometry (LC/MS). HP-NAP was used to stimulate human neutrophils for characterization of the purified recombinant HP-NAP. HP-NAP-stimulated neutrophils increased the production of reactive oxygen species (ROS) which was measured by using nitro blue tetrazolium chloride (NBT) dye reduction assay and luminol-dependent chemiluminescence assay. Interestingly, recombinant HP-NAP promoted the secretion of myeloperoxidase (MPO) in human neutrophils, which was a novel finding for the function of HP-NAP. These results indicate that recombinant HP-NAP may have ability to activate human neutrophils. Furthermore, recombinant HP-NAP in this expression system can be used to investigate the role of HP-NAP in H. pylori infection and to develop the vaccine against H. pylori.