title: Aging and PMN response to P. aeruginosa infection.
abstract: OBJECTIVE
  Alterations in immune system function associated with aging may contribute to increased morbidity in this population of individuals. The current studies were performed to determine aging-related changes in polymorphonuclear neutrophil (PMN) function after corneal infection with Pseudomonas aeruginosa.
  
  
  METHODS
  Total PMN number, macrophage inflammatory protein (MIP)-2 mRNA and protein expression, and ocular bacterial load were determined in 8-week- and 12-month-old inbred BALB/c mice at various times after infection with P. aeruginosa. In addition, 12-month-old mice were treated systemically with the MIP-2 polyclonal antibody (pAb) to determine the effects of MIP-2 neutralization on ocular disease and PMN recruitment.
  
  
  RESULTS
  Histologically, PMN infiltration into the cornea of 12-month-old mice was delayed initially and was associated with an inability to reduce bacterial load at later postinfection (PI) times. In addition, a significantly greater number of PMNs were found in the cornea of 12-month-old mice at later PI times. The increase in PMN number in 12-month-old mice correlated with a persistence of MIP-2 expression in cornea at these later times. Systemic treatment of 12-month-old mice with neutralizing MIP-2 pAb versus normal rabbit serum (NRS) resulted in reduced corneal PMN number and ocular disease.
  
  
  CONCLUSIONS
  These data provide evidence that persistence of PMN in the cornea of 12-month-old mice contributes to corneal tissue destruction after P. aeruginosa challenge. Further evidence also is provided that the chemoattractant MIP-2 contributes to the altered PMN response in these animals.
authors.affiliation: Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Kernacki
authors.forename: R P
authors.initials: RP
authors.lastname: Barrett
authors.forename: S A
authors.initials: SA
authors.lastname: McClellan
authors.forename: L D
authors.initials: LD
authors.lastname: Hazlett
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D054426:Chemokine CXCL2; D003320:Corneal Ulcer / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D015818:Eye Infections, Bacterial / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D007958:Leukocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C; D015846:Monokines / Q000235:genetics / Q000276:immunology; D020556:Neutrophil Infiltration / Q000276:immunology; D009504:Neutrophils / Q000502:physiology*; D011552:Pseudomonas Infections / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D054426:Chemokine CXCL2; D015846:Monokines; D012333:RNA, Messenger