title: Oral neutrophils display a site-specific phenotype characterized by expression of T-cell receptors.
abstract: BACKGROUND
  Neutrophils, key cells of the innate immune system, were previously thought to be terminally differentiated cells, incapable of altering their gene expression after differentiation and maturation in the bone marrow. Only recently has it been shown that neutrophils perform rapid and complex changes in gene expression during inflammatory responses. Previous work by the authors has demonstrated differences in reactive oxygen species production between oral and peripheral blood neutrophils isolated from patients with chronic periodontitis, suggesting that oral neutrophils present with a unique oral phenotype. Understanding differences in the neutrophil transcriptome after transit from circulation into the site of inflammation will give new insights into how these innate immune cells function during inflammation.
  
  
  METHODS
  Venous blood and oral rinse samples were obtained from five healthy participants. Blood neutrophils were isolated using a standard gradient method. Oral neutrophils were isolated through nylon mesh filters of different pore sizes (40 to 10 μm). RNA was purified from isolated neutrophils, and gene expression microarray analysis was completed. Results were confirmed by quantitative reverse transcription-polymerase chain reaction and immunofluorescence microscopy.
  
  
  RESULTS
  Oral neutrophil isolation, which is critical when analyzing gene expression with samples clear of epithelial cell contamination, was optimized. It was also demonstrated that oral neutrophils present with a significant increase in T-cell receptor expression compared with circulating neutrophils, suggesting a role for oral neutrophils in crosstalk between the innate and adaptive immune system in the mouth.
  
  
  CONCLUSIONS
  To the best of the authors' knowledge, it is demonstrated for the first time that, compared with circulating neutrophils, oral neutrophils present a site-specific gene expression profile in healthy individuals.
authors.affiliation: Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, Toronto, ON.
authors.forename: Flavia S
authors.initials: FS
authors.lastname: Lakschevitz
authors.forename: Guy M
authors.initials: GM
authors.lastname: Aboodi
authors.forename: Michael
authors.initials: M
authors.lastname: Glogauer
mesh_terms: D056704:Adaptive Immunity / Q000235:genetics / Q000276:immunology; D000328:Adult; D001769:Blood; D002469:Cell Separation; D018925:Chemokines / Q000032:analysis; D016207:Cytokines / Q000032:analysis; D003774:Dental Plaque Index; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology; D008297:Male; D046228:Microarray Analysis; D009061:Mouth Mucosa / Q000166:cytology*; D005810:Multigene Family / Q000235:genetics; D009504:Neutrophils / Q000145:classification / Q000276:immunology*; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000145:classification; D010641:Phenotype; D012313:RNA / Q000032:analysis; D020239:Receptor Cross-Talk / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000032:analysis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D018925:Chemokines; D016207:Cytokines; D011948:Receptors, Antigen, T-Cell; D012313:RNA