title: Expression of human beta-defensins in intraocular tissues.
abstract: OBJECTIVE
  Defensins are naturally occurring antimicrobial peptides. Recently the authors published evidence of defensin production by the human ocular surface. A study was undertaken to look for intraocular defensins that may account for unexplained antimicrobial activity of intraocular fluids.
  
  
  METHODS
  Reverse transcription-polymerase chain reaction (RT-PCR) was performed on human postmortem ciliary body samples for beta defensins-1 (HBD-1) and beta defensin-2 (HBD-2), and alpha defensins 5 and 6. Induction of defensins by cytokines was analyzed in cultured human ciliary body epithelial (CBE) and retinal pigment epithelial (RPE) cells. Polyclonal antibodies were used to immunoblot aqueous and vitreous to detect HBD-1 and HBD-2 and to estimate their concentration.
  
  
  RESULTS
  RT-PCR revealed constitutive HBD-1 message in ciliary body. HBD-2 and alpha defensin 5 and 6 messages were absent. HBD-2 message was induced by cytokine stimulation of both CBE and RPE cells. Immunoblots of vitreous and aqueous stained positively for HBD-1 but not HBD-2. The estimated aqueous concentration of HBD-1 was less than 16 ng/ml.
  
  
  CONCLUSIONS
  This study demonstrates that HBD-1 is constitutively present in the aqueous and vitreous, probably at sub-bacteriocidal concentrations. HBD-2 was absent from aqueous, but cytokine stimulation studies suggest that it may be generated in response to inflammatory cytokines during infections. HBD-2 has a wider antibacterial spectrum, is 10-fold more potent, and may play a more significant role in antimicrobial defense than HBD-1. The use of defensins therapeutically may be indicated; however, caution is required because defensins also promote cell proliferation and fibrin formation, which are 2 key elements in ocular scarring processes such as proliferative vitreoretinopathy.
authors.affiliation: Larry A. Donoso Laboratory for Eye Research, Academic Department of Ophthalmology, Queen's Medical Centre, University Hospital Nottingham, United Kingdom.
authors.forename: R J
authors.initials: RJ
authors.lastname: Haynes
authors.forename: J E
authors.initials: JE
authors.lastname: McElveen
authors.forename: H S
authors.initials: HS
authors.lastname: Dua
authors.forename: P J
authors.initials: PJ
authors.lastname: Tighe
authors.forename: J
authors.initials: J
authors.lastname: Liversidge
mesh_terms: D001082:Aqueous Humor / Q000378:metabolism; D002478:Cells, Cultured; D002924:Ciliary Body / Q000187:drug effects / Q000378:metabolism*; D016207:Cytokines / Q000494:pharmacology; D017931:DNA Primers / Q000737:chemistry; D023082:Defensins; D015870:Gene Expression; D006801:Humans; D015151:Immunoblotting; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000378:metabolism*; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012313:RNA / Q000302:isolation & purification; D012333:RNA, Messenger / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014822:Vitreous Body / Q000378:metabolism; D023083:beta-Defensins
chemical_list: D016207:Cytokines; C406407:DEFB1 protein, human; D017931:DNA Primers; D023082:Defensins; D011506:Proteins; D012333:RNA, Messenger; D023083:beta-Defensins; D012313:RNA