title: Automated image-based assay for evaluation of HIV neutralization and cell-to-cell fusion inhibition.
abstract: BACKGROUND
  Standardized techniques to detect HIV-neutralizing antibody responses are of great importance in the search for an HIV vaccine.
  
  
  METHODS
  Here, we present a high-throughput, high-content automated plaque reduction (APR) assay based on automated microscopy and image analysis that allows evaluation of neutralization and inhibition of cell-cell fusion within the same assay. Neutralization of virus particles is measured as a reduction in the number of fluorescent plaques, and inhibition of cell-cell fusion as a reduction in plaque area.
  
  
  RESULTS
  We found neutralization strength to be a significant factor in the ability of virus to form syncytia. Further, we introduce the inhibitory concentration of plaque area reduction (ICpar) as an additional measure of antiviral activity, i.e. fusion inhibition.
  
  
  CONCLUSIONS
  We present an automated image based high-throughput, high-content HIV plaque reduction assay. This allows, for the first time, simultaneous evaluation of neutralization and inhibition of cell-cell fusion within the same assay, by quantifying the reduction in number of plaques and mean plaque area, respectively. Inhibition of cell-to-cell fusion requires higher quantities of inhibitory reagent than inhibition of virus neutralization.
authors.affiliation: Department of Laboratory Medicine, Lund University, Lund, Sweden. enas.sheik-khalil@med.lu.se.
authors.forename: Enas
authors.initials: E
authors.lastname: Sheik-Khalil
authors.forename: Mark-Anthony
authors.initials: MA
authors.lastname: Bray
authors.forename: Gülsen
authors.initials: G
authors.lastname: Özkaya Şahin
authors.forename: Gabriella
authors.initials: G
authors.lastname: Scarlatti
authors.forename: Marianne
authors.initials: M
authors.lastname: Jansson
authors.forename: Anne E
authors.initials: AE
authors.lastname: Carpenter
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Fenyö
mesh_terms: D057205:Automation, Laboratory; D002459:Cell Fusion; D002478:Cells, Cultured; D015658:HIV Infections / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007963:Leukocytes, Mononuclear / Q000502:physiology / Q000821:virology; D008856:Microscopy, Fluorescence; D009500:Neutralization Tests; D010948:Viral Plaque Assay