title: A role for C5 and C5a-ase in the acute neutrophil response to group B streptococcal infections.
abstract: Congenic C5-deficient and C5-sufficient mice were infected with group B streptococci (GBS) to determine if the polymorphonuclear leukocyte (PMNL) chemoattractant C5a contributes to PMNL recruitment in GBS infection and if GBS C5a-ase reduces C5a-induced PMNL recruitment in vivo. PMNL accumulation was greater in the peritoneum and air spaces of C5-sufficient mice than in C5-deficient mice. Administration of human C5 to C5-deficient mice caused a significant increase in PMNL recruitment following infection with C5a-ase-negative GBS. GBS C5a-ase did not reduce PMNL accumulation in C5-sufficient mice but reduced PMNL recruitment in C5-deficient mice reconstituted with human C5. These data indicate that C5a is important for rapid PMNL recruitment to sites of GBS infection and that GBS C5a-ase inactivates human, but not murine, C5a in vivo. Reduction of the acute inflammatory response by C5a-ase likely contributes to GBS virulence in human neonates.
authors.affiliation: Department of Pediatrics, University of Utah School of Medicine, Salt Lake City 84132, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Bohnsack
authors.forename: K
authors.initials: K
authors.lastname: Widjaja
authors.forename: S
authors.initials: S
authors.lastname: Ghazizadeh
authors.forename: C E
authors.initials: CE
authors.lastname: Rubens
authors.forename: D R
authors.initials: DR
authors.lastname: Hillyard
authors.forename: C J
authors.initials: CJ
authors.lastname: Parker
authors.forename: K H
authors.initials: KH
authors.lastname: Albertine
authors.forename: H R
authors.initials: HR
authors.lastname: Hill
mesh_terms: D018829:Adhesins, Bacterial; D000818:Animals; D003182:Complement C5 / Q000502:physiology*; D003169:Complement Inactivator Proteins / Q000502:physiology*; D010450:Endopeptidases / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D009504:Neutrophils / Q000276:immunology*; D013290:Streptococcal Infections / Q000276:immunology*; D013292:Streptococcus agalactiae / Q000276:immunology*
chemical_list: D018829:Adhesins, Bacterial; D003182:Complement C5; D003169:Complement Inactivator Proteins; D010450:Endopeptidases; C053088:C5a peptidase