title: Anti-adenoviral effects of human cationic antimicrobial protein-18/LL-37, an antimicrobial peptide, by quantitative polymerase chain reaction.
abstract: OBJECTIVE
  Antimicrobial peptides have an important role in self-protection of the ocular surface. Human cationic antimicrobial protein (hCAP)-18 is a linear, α-helical peptide that consists of a conserved pro-sequence called a cathelin-like domain and a C-terminal peptide named LL-37. We investigated the in vitro anti-adenoviral activity of hCAP-18/LL-37 in several adenovirus types, inducing keratoconjunctivitis.
  
  
  METHODS
  A549 cells were used for viral cell culture, and human adenovirus (HAdV) types 3 (HAdV3, species B), 4 (species E), 8, 19a, and 37 (species D) were used. The cytotoxicity of LL-37 was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay to obtain 50% cytotoxic concentration. After pretreatment of A549 cells with serial dilutions of LL-37 for 24 hours, adenovirus was cultured for seven days, and adenoviral DNA was quantitatively measured by real-time polymerase chain reaction (PCR).
  
  
  RESULTS
  The 50% effective concentration of LL-37 obtained by real-time PCR ranged between 118 and 270 µM. LL-37 showed a significant inhibitory effect on adenoviral proliferation in all adenovirus types except HAdV4 in a dose-dependent manner.
  
  
  CONCLUSIONS
  LL-37 has significant inhibitory activity against HAdV3, 8, and 19, which induce keratoconjunctivitis. These results indicate that hCAP-18/LL-37 may be a possible candidate for the treatment of HAdV keratoconjunctivitis.
authors.affiliation: Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Uchio
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Inoue
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Kadonosono
mesh_terms: D000230:Adenocarcinoma; D000256:Adenoviridae / Q000187:drug effects* / Q000235:genetics*; D000257:Adenoviridae Infections / Q000188:drug therapy* / Q000821:virology; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D045744:Cell Line, Tumor; D004279:DNA, Viral / Q000235:genetics; D006801:Humans; D007637:Keratoconjunctivitis / Q000188:drug therapy* / Q000821:virology; D008175:Lung Neoplasms; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D004279:DNA, Viral; D054804:Cathelicidins
keywords: Adenoviridae; Antiviral agents; Human cationic antimicrobial protein-18; LL-37; Viral conjunctivitis