title: Secretory leukocyte protease inhibitor binds to Neisseria gonorrhoeae outer membrane opacity protein and is bactericidal.
abstract: OBJECTIVE
  Secretory leukocyte protease inhibitor (SLPI) is an innate immune peptide present on the genitourinary tract mucosa that has antimicrobial activity. In this study, we investigated the interaction of SLPI with Neisseria gonorrhoeae.
  
  
  METHODS
  ELISA and far-Western blots were used to analyze binding of SLPI to gonococci. The binding site for SLPI was identified by tryptic digests and mass spectrometry. Antimicrobial activity of SLPI for gonococci was determined using bactericidal assays. SLPI protein levels in cell supernatants were measured by ELISA, and SLPI mRNA levels were assessed by quantitative RT-PCR.
  
  
  RESULTS
  SLPI bound directly to the gonococcal Opa protein and was bactericidal. Epithelial cells from the reproductive tract constitutively expressed SLPI at different levels. Gonococcal infection of cells did not affect SLPI expression.
  
  
  CONCLUSIONS
  We conclude that SLPI is bactericidal for gonococci and is expressed by reproductive tract epithelial cells and thus is likely to play a role in the pathogenesis of gonococcal infection.
authors.affiliation: Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University, Springfield, IL, USA.
authors.forename: Morris D
authors.initials: MD
authors.lastname: Cooper
authors.forename: Melissa H
authors.initials: MH
authors.lastname: Roberts
authors.forename: Ona L
authors.initials: OL
authors.lastname: Barauskas
authors.forename: Gary A
authors.initials: GA
authors.lastname: Jarvis
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D002460:Cell Line; D005786:Gene Expression Regulation / Q000276:immunology; D006069:Gonorrhea / Q000276:immunology*; D054884:Host-Pathogen Interactions; D006801:Humans; D018928:Immunity, Mucosal; D009344:Neisseria gonorrhoeae / Q000276:immunology*; D011485:Protein Binding; D053481:Secretory Leukocyte Peptidase Inhibitor / Q000235:genetics / Q000378:metabolism*; D014566:Urogenital System / Q000276:immunology* / Q000382:microbiology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D053481:Secretory Leukocyte Peptidase Inhibitor; C090348:Opa protein, Neisseria