title: West Nile virus in blood: stability, distribution, and susceptibility to PEN110 inactivation.
abstract: BACKGROUND
  The outbreak of West Nile virus (WNV) is the most recent reminder that the blood supply continues to be vulnerable to emerging and reemerging pathogens. A potentially prospective approach to reducing the risk of transfusion-transmitted infections of a known or newly emerging microbe is implementation of a broad-spectrum pathogen reduction technology. The purpose of this study was to evaluate the susceptibility of WNV to PEN110 inactivation in RBCs and to characterize the WNV interaction with blood, including the stability of WNV in RBCs stored at 1 to 6 degrees C, its distribution and infectivity, and its ability to infect WBCs.
  
  
  METHODS
  Inactivation was performed with three WNV isolates spiked into WBC-reduced RBCs. The stability of the virus was evaluated by spiking two viral loads into RBCs followed by storing at 1 to 6 degrees C for up to 42 days. The distribution of the virus in plasma, RBCs, and PBMCs was evaluated with whole blood from infected hamsters. Finally, in vitro propagation of WNV was evaluated with the THP-1 cell line and primary monocytes.
  
  
  RESULTS
  The kinetics of PEN110 inactivation of WNV isolates RI-44, NJ-176, and 99-3494031 were fast and complete within 24 hours with reduction factors of 5 to 7 log plaque-forming units per mL. WNV remained infectious for up to 42 days at 1 to 6 degrees C. The WNV titers in whole blood, plasma, RBCs, and PBMC fractions were equally distributed and ranged from 2 to 3 log tissue culture infectious dose 50 percent per mL. Productive infection of stimulated monocytes and THP-1 cells was also demonstrated.
  
  
  CONCLUSIONS
  These studies demonstrated that PEN110 efficiently inactivated WNV in RBCs and whole blood from infected hamsters to the limit of detection. WNV survived in RBCs stored at 1 to 6 degrees C with a gradual loss of titer but infectivity could still be observed for up to 42 days. In addition, it was observed that WNV was equally distributed in all blood fractions including PBMCs and it was possible to establish productive infection of a human monocytic cell line and stimulated human monocytes.
authors.affiliation: V.I. Technologies, Inc., Watertown, Massachusetts 02472, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mather
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takeda
authors.forename: Jodie
authors.initials: J
authors.lastname: Tassello
authors.forename: Asa
authors.initials: A
authors.lastname: Ohagen
authors.forename: Diana
authors.initials: D
authors.lastname: Serebryanik
authors.forename: Ed
authors.initials: E
authors.lastname: Kramer
authors.forename: Fred
authors.initials: F
authors.lastname: Brown
authors.forename: Robert
authors.initials: R
authors.lastname: Tesh
authors.forename: Bernadette
authors.initials: B
authors.lastname: Alford
authors.forename: John
authors.initials: J
authors.lastname: Chapman
authors.forename: Aris
authors.initials: A
authors.lastname: Lazo
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001769:Blood / Q000821:virology*; D001771:Blood Banks; D001793:Blood Preservation; D002522:Chlorocebus aethiops; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000821:virology; D006801:Humans; D007700:Kinetics; D007937:Leukapheresis; D011073:Polyamines / Q000008:administration & dosage / Q000494:pharmacology*; D014709:Vero Cells; D038301:Virus Inactivation; D014779:Virus Replication; D014901:West Nile Fever / Q000097:blood / Q000821:virology; D014902:West Nile virus / Q000187:drug effects* / Q000472:pathogenicity / Q000502:physiology
chemical_list: D000998:Antiviral Agents; C451719:PEN 110; D011073:Polyamines