title: Vaccine-induced immunity against Helicobacter pylori in the absence of IL-17A.
abstract: BACKGROUND
  Helicobacter pylori (H. pylori) is a gram negative bacterium that can cause diseases such as peptic ulcers and gastric cancer. IL-17A, a proinflammatory cytokine that can induce the production of CXC chemokines for neutrophil recruitment, has recently been shown to be elevated in both H. pylori-infected patients and mice. Furthermore, studies in mouse models of vaccination have reported levels significantly increased over infected, unimmunized mice and blocking of IL-17A during the challenge phase in immunized mice reduces protective immunity. Because many aspects of immunity had redundant or compensatory mechanisms, we investigated whether mice could be protectively immunized when IL-17A function is absent during the entire immune response using IL-17A and IL-17A receptor knockout (KO) mice immunized against H. pylori.
  
  
  METHODS
  Gastric biopsies were harvested from naïve, unimmunized/challenged, and immunized/challenged wild type (WT) and KO mice and analyzed for inflammation, neutrophil, and bacterial levels. Groups of IL-17A KO mice were also treated with anti-IFNγ or control antibodies.
  
  
  RESULTS
  Surprisingly, all groups of immunized KO mice reduced their bacterial loads comparably to WT mice. The gastric neutrophil counts did not vary significantly between IL-17A KO and WT mice, whereas IL-17RA KO mice had on average a four-fold decrease compared to WT. Additionally, we performed an immunization study with CXCR2 KO mice and observed significant gastric neutrophils and reduction in bacterial load.
  
  
  CONCLUSIONS
  These data suggest that there are compensatory mechanisms for protection against H. pylori and for neutrophil recruitment in the absence of an IL-17A-CXC chemokine pathway.
authors.affiliation: Department of Pathology, Case Western Reserve University, School of Medicine, Cleveland, OH, USA.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: DeLyria
authors.forename: John G
authors.initials: JG
authors.lastname: Nedrud
authors.forename: Peter B
authors.initials: PB
authors.lastname: Ernst
authors.forename: Mohammad S
authors.initials: MS
authors.lastname: Alam
authors.forename: Raymond W
authors.initials: RW
authors.lastname: Redline
authors.forename: Hua
authors.initials: H
authors.lastname: Ding
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Czinn
authors.forename: Jinghua
authors.initials: J
authors.lastname: Xu
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Blanchard
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D005753:Gastric Mucosa / Q000276:immunology / Q000382:microbiology; D016481:Helicobacter Infections / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007114:Immunization; D020381:Interleukin-17 / Q000172:deficiency* / Q000235:genetics / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009504:Neutrophils / Q000276:immunology; D053722:Receptors, Interleukin-17 / Q000235:genetics / Q000276:immunology
chemical_list: D001428:Bacterial Vaccines; D020381:Interleukin-17; D053722:Receptors, Interleukin-17