title: A low molecular weight factor is a significant mediator of non-opsonic neutrophil activation by Helicobacter pylori.
abstract: Helicobacter pylori is believed to trigger neutrophil activation through several factors, including the H. pylori neutrophil-activating protein (HpNAP). The aim of this study was to characterise the factors within H. pylori cell-free extracts that stimulate neutrophil activation. Neutrophil activation was found to be dose-dependent and exhibited considerable variation between different clinical isolates. Activity was attributable to more than one protein factor. A low mol. wt fraction of <3 kDa was found to contribute a large proportion of the neutrophil-stimulating activity within H. pylori cell-free extract. Additional activity was provided by a high mol. wt fraction, possibly representing HpNAP. An inhibition ELISA and neutralisation experiments failed to identify or exclude formyl methionyl leucyl phenylalanine as the active factor within the low mol. wt fraction. The importance of the putative, low mol. wt neutrophil-activating factor may have been overlooked by those studies that have used concentrated H. pylori extracts.
authors.affiliation: *Department of Microbiology and Immunology, James Cook University and †Department of Medicine, North Queensland Clinical School, University of Queensland, Australia.
authors.forename: Alison
authors.initials: A
authors.lastname: Leakey
authors.affiliation: *Department of Microbiology and Immunology, James Cook University and †Department of Medicine, North Queensland Clinical School, University of Queensland, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Hirst
authors.affiliation: *Department of Microbiology and Immunology, James Cook University and †Department of Medicine, North Queensland Clinical School, University of Queensland, Australia.
authors.forename: Justin
authors.initials: J
authors.lastname: LA Brooy
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000502:physiology*; D002850:Chromatography, Gel; D004306:Dose-Response Relationship, Immunologic; D010450:Endopeptidases / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000032:analysis; D009500:Neutralization Tests; D018375:Neutrophil Activation / Q000502:physiology*; D009504:Neutrophils / Q000276:immunology*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; C092412:neutrophil-activating protein A, Helicobacter pylori; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010450:Endopeptidases