title: Entry kinetics and cell-cell transmission of surface-bound retroviral vector particles.
abstract: BACKGROUND
  Transduction with recombinant HIV-1 derived lentivirus vectors is a multi-step process initiated by surface attachment and subsequent receptor-directed uptake into the target cell. We previously reported the retention of vesicular stomatitis virus G protein pseudotyped particles on murine progenitor cells and their delayed cell-cell transfer.
  
  
  METHODS
  To examine the underlying mechanism in more detail, we used a combination of approaches focused on investigating the role of receptor-independent factors in modulating attachment.
  
  
  RESULTS
  The investigation of synchronized transduction reveals cell-type specific rates of vector particle clearance with substantial delays during particle entry into murine hematopoietic progenitor cells. The observed uptake kinetics from the surface of the 1 degrees cell correlate inversely with the magnitude of transfer to 2 degrees targets, corresponding with our initial observation of preferential cell-cell transfer in the context of brief vector exposures. We further demonstrate that vector particle entry into cells is associated with the cell-type specific abundance of extracellular matrix fibronectin. Residual particle-extracellular fibronectin matrix binding and 2 degrees transfer can be competitively disrupted by heparin exposure without affecting murine progenitor homing and repopulation.
  
  
  CONCLUSIONS
  Although cellular attachment factors, including fibronectin, aid gene transfer by colocalizing particles to cells and disfavoring early dissociation from targets, they also appear to stabilize particles on the cell surface. The present study highlights the inadvertent consequences for cell entry and cell-cell transfer.
authors.affiliation: Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
authors.forename: Lee S
authors.initials: LS
authors.lastname: O'Neill
authors.forename: Amy M
authors.initials: AM
authors.lastname: Skinner
authors.forename: Josha A
authors.initials: JA
authors.lastname: Woodward
authors.forename: Peter
authors.initials: P
authors.lastname: Kurre
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000821:virology; D002450:Cell Communication / Q000187:drug effects; D002460:Cell Line; D019070:Cell Lineage / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000821:virology*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005822:Genetic Vectors / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D051379:Mice; D010447:Peptide Hydrolases / Q000378:metabolism; D011533:Proviruses / Q000187:drug effects / Q000378:metabolism; D012190:Retroviridae / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D014161:Transduction, Genetic; D014771:Virion / Q000187:drug effects / Q000378:metabolism*; D016662:Virus Integration / Q000187:drug effects; D053586:Virus Internalization / Q000187:drug effects; D014916:Whole-Body Irradiation
chemical_list: D005353:Fibronectins; D049452:Green Fluorescent Proteins; D006493:Heparin; D010447:Peptide Hydrolases