title: Ability of vaccine strain induced antibodies to neutralize field isolates of caliciviruses from Swedish cats.
abstract: BACKGROUND
  Feline calicivirus (FCV) is a common cause of upper respiratory tract disease in cats worldwide. Its characteristically high mutation rate leads to escape from the humoral immune response induced by natural infection and/or vaccination and consequently vaccines are not always effective against field isolates. Thus, there is a need to continuously investigate the ability of FCV vaccine strain-induced antibodies to neutralize field isolates.
  
  
  METHODS
  Seventy-eight field isolates of FCV isolated during the years 2008-2012 from Swedish cats displaying clinical signs of upper respiratory tract disease were examined in this study. The field isolates were tested for cross-neutralization using a panel of eight anti-sera raised in four pairs of cats following infection with four vaccine strains (F9, 255, G1 and 431).
  
  
  RESULTS
  The anti-sera raised against F9 and 255 neutralised 20.5 and 11.5 %, and 47.4 and 64.1 % of field isolates tested, respectively. The anti-sera against the more recently introduced vaccine strains G1 and 431 neutralized 33.3 and 55.1 % (strain G1) or 69.2 and 89.7 % (strain 431) of the field isolates with titres ≥5. [corrected]. Dual vaccine strains displayed a higher cross-neutralization.
  
  
  CONCLUSIONS
  This study confirms previous observations that more recently introduced vaccine strains induce antibodies with a higher neutralizing capacity compared to vaccine strains that have been used extensively over a long period of time. This study also suggests that dual FCV vaccine strains might neutralize more field isolates compared to single vaccine strains. Vaccine strains should ideally be selected based on updated knowledge on the antigenic properties of field isolates in the local setting, and there is thus a need for continuously studying the evolution of FCV together with the neutralizing capacity of vaccine strain induced antibodies against field isolates at a national and/or regional level.
authors.affiliation: Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden. Jonas.Wensman@slu.se.
authors.forename: Jonas Johansson
authors.initials: JJ
authors.lastname: Wensman
authors.affiliation: MRC-University of Glasgow Centre for Virus Research, Glasgow, UK. Ayman.Samman@glasgow.ac.uk.
authors.forename: Ayman
authors.initials: A
authors.lastname: Samman
authors.affiliation: Department of Virology, Immune Biology and Parasitology, National Veterinary Institute, Uppsala, Sweden. anna.lindhe@sva.se.
authors.forename: Anna
authors.initials: A
authors.lastname: Lindhe
authors.affiliation: Global Technical Services, Merial, Lyon, France. Jean-christophe.THIBAULT@merial.com.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Thibault
authors.affiliation: Department of Virology, Immune Biology and Parasitology, National Veterinary Institute, Uppsala, Sweden. louise.t.berndtsson@sva.se.
authors.forename: Louise Treiberg
authors.initials: LT
authors.lastname: Berndtsson
authors.affiliation: MRC-University of Glasgow Centre for Virus Research, Glasgow, UK. margaret.hosie@glasgow.ac.uk.
authors.forename: Margaret J
authors.initials: MJ
authors.lastname: Hosie
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D017250:Caliciviridae Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D017927:Calicivirus, Feline / Q000276:immunology*; D002371:Cat Diseases / Q000276:immunology* / Q000821:virology; D002415:Cats; D009500:Neutralization Tests / Q000662:veterinary; D013548:Sweden; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D014765:Viral Vaccines