title: Live-attenuated measles virus vaccine targets dendritic cells and macrophages in muscle of nonhuman primates.
abstract: Although live-attenuated measles virus (MV) vaccines have been used successfully for over 50 years, the target cells that sustain virus replication in vivo are still unknown. We generated a reverse genetics system for the live-attenuated MV vaccine strain Edmonston-Zagreb (EZ), allowing recovery of recombinant (r)MV(EZ). Three recombinant viruses were generated that contained the open reading frame encoding enhanced green fluorescent protein (EGFP) within an additional transcriptional unit (ATU) at various positions within the genome. rMV(EZ)EGFP(1), rMV(EZ)EGFP(3), and rMV(EZ)EGFP(6) contained the ATU upstream of the N gene, following the P gene, and following the H gene, respectively. The viruses were compared in vitro by growth curves, which indicated that rMV(EZ)EGFP(1) was overattenuated. Intratracheal infection of cynomolgus macaques with these recombinant viruses revealed differences in immunogenicity. rMV(EZ)EGFP(1) and rMV(EZ)EGFP(6) did not induce satisfactory serum antibody responses, whereas both in vitro and in vivo rMV(EZ)EGFP(3) was functionally equivalent to the commercial MV(EZ)-containing vaccine. Intramuscular vaccination of macaques with rMV(EZ)EGFP(3) resulted in the identification of EGFP(+) cells in the muscle at days 3, 5, and 7 postvaccination. Phenotypic characterization of these cells demonstrated that muscle cells were not infected and that dendritic cells and macrophages were the predominant target cells of live-attenuated MV.
  
  
  OBJECTIVE
  Even though MV strain Edmonston-Zagreb has long been used as a live-attenuated vaccine (LAV) to protect against measles, nothing is known about the primary cells in which the virus replicates in vivo. This is vital information given the push to move toward needle-free routes of vaccination, since vaccine virus replication is essential for vaccination efficacy. We have generated a number of recombinant MV strains expressing enhanced green fluorescent protein. The virus that best mimicked the nonrecombinant vaccine virus was formulated according to protocols for production of commercial vaccine virus batches, and was subsequently used to assess viral tropism in nonhuman primates. The virus primarily replicated in professional antigen-presenting cells, which may explain why this LAV is so immunogenic and efficacious.
authors.affiliation: Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA.
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Rennick
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Rory D
authors.initials: RD
authors.lastname: de Vries
authors.affiliation: Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Carsillo
authors.affiliation: School of Medicine, Dentistry and Biomedical Sciences, The Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Ken
authors.initials: K
authors.lastname: Lemon
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Geert
authors.initials: G
authors.lastname: van Amerongen
authors.affiliation: Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Ludlow
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: D Tien
authors.initials: DT
authors.lastname: Nguyen
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Selma
authors.initials: S
authors.lastname: Yüksel
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: R Joyce
authors.initials: RJ
authors.lastname: Verburgh
authors.affiliation: School of Medicine, Dentistry and Biomedical Sciences, The Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Paula
authors.initials: P
authors.lastname: Haddock
authors.affiliation: Tissue Pathology, Belfast Health and Social Care Trust, The Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: McQuaid
authors.affiliation: Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA pduprex@bu.edu.
authors.forename: W Paul
authors.initials: WP
authors.lastname: Duprex
authors.affiliation: Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Rik L
authors.initials: RL
authors.lastname: de Swart
mesh_terms: D000818:Animals; D003713:Dendritic Cells / Q000276:immunology* / Q000821:virology*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008252:Macaca fascicularis; D008264:Macrophages / Q000276:immunology* / Q000821:virology*; D008297:Male; D008458:Measles Vaccine / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D008459:Measles virus / Q000276:immunology*; D009132:Muscles / Q000276:immunology*; D013194:Staining and Labeling; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D008458:Measles Vaccine; D014613:Vaccines, Attenuated; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins