title: Effects of physiologic concentrations of l-lysine on in vitro replication of feline herpesvirus 1.
abstract: OBJECTIVE
  To evaluate the effects of various concentrations of l-lysine on in vitro replication of feline herpesvirus 1 (FHV-1).
  
  
  METHODS
  Cultures of Crandell-Rees feline kidney (CRFK) cells.
  
  
  METHODS
  CRFK cells were inoculated with FHV-1 and maintained in media with 20 combinations of l-arginine and l-lysine concentrations. Changes in cell viability were monitored by continuous measurement of electrical impedance of cultured cells and by observation of viral cytopathic effects. Viral load was determined by use of quantitative PCR assay in supernatants obtained from infected cultures at specified time points.
  
  
  RESULTS
  Increases in l-lysine concentration had no effect on the kinetics of cell death in FHV-1-infected cultures. There was also no significant effect (r(2) < 0.1) on viral DNA load for l-arginine concentrations ≥ 12 μg/mL There was a significant effect of increases in l-lysine concentration on viral DNA load in media supplemented with 6 μg of l-arginine/mL (mean ± SD slope, -4,641 ± 1,626 units; adjusted r(2) = 0.45). However, the difference between the lowest (1 × 10(6.28) copies/μL) and highest (1 × 10(6.86) copies/μL) FHV-1 DNA load in these media was < 1 logarithm.
  
  
  CONCLUSIONS
  The difference in FHV-1 DNA load was unlikely to be biologically important. Various l-lysine concentrations did not inhibit in vitro replication of FHV-1 at l-arginine concentrations sufficient to maintain cell growth. This conclusion was consistent with results of other studies in which investigators have not detected a consistently beneficial effect when l-lysine is administered to FHV-1-infected cats.
authors.affiliation: Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North 4410, New Zealand.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Cave
authors.forename: Kathryn
authors.initials: K
authors.lastname: Dennis
authors.forename: Gaya
authors.initials: G
authors.lastname: Gopakumar
authors.forename: Magda
authors.initials: M
authors.lastname: Dunowska
mesh_terms: D000818:Animals; D002415:Cats; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000032:analysis; D007700:Kinetics; D008239:Lysine / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012044:Regression Analysis; D018140:Varicellovirus / Q000502:physiology*; D019562:Viral Load; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D017931:DNA Primers; D004279:DNA, Viral; D008239:Lysine