title: Vaccination with recombinant paramyosin against the bovine lungworm Dictyocaulus viviparus considerably reduces worm burden and larvae shedding.
abstract: BACKGROUND
  The lungworm Dictyocaulus viviparus, causing parasitic bronchitis in cattle, induces a temporary protective immunity that prevents clinical disease. A radiation-attenuated larvae based vaccine is commercially available in a few European countries, but has the disadvantages of a live vaccine. As a recombinant subunit vaccine would overcome these disadvantages, the parasite's muscle protein paramyosin (PMY) was tested as a recombinant vaccine antigen.
  
  
  METHODS
  D. viviparus-PMY was recombinantly expressed in Escherichia coli as a glutathione-S-transferase (GST)-fused protein. Emulsified in adjuvant Saponin Quil A, the protein was given intramuscularly into calves. Two independent recombinant PMY (rPMY) vaccination trials with negative control groups (first trial: adjuvant only; second trial: non-fused GST) as well as an additional positive control group in the second trial, using the Bovilis Dictol live vaccine to verify vaccination results, were performed. To determine the vaccination success, shedding of larvae as well as worm burden and worm sizes were analyzed. Additionally, ELISA-based determination of development of immunglobulins IgM, IgA, IgE, IgG as well as the subclasses IgG1 and IgG2 was performed. To analyze PMY localization in the bovine lungworm, immunohistochemical staining of adult worms was carried out.
  
  
  RESULTS
  Immunohistochemical staining revealed that PMY is part of the bovine lungworm's pharyngeal and body wall muscles. Vaccination with rPMY resulted in 47% [geometric mean: 67%] and 57% (geometric mean: 71%) reduction of larvae shedding in the first and second vaccination trial, respectively. Worm burden was reduced by 54% (geometric mean: 86%) and 31% (geometric mean: 68%), respectively, and worms of rPMY-vaccinated cattle were significantly shorter in both trials. Furthermore, ELISAs showed a clear antibody response towards rPMY with exception of IgE for which titers could not be detected. After challenge infection, rPMY antibodies were only exceptionally elevated among study animals indicating PMY to be a hidden antigen.
  
  
  CONCLUSIONS
  Even though vaccination with the attenuated live vaccine was with 94% (geometric mean: 95%) reduction in larvae shedding and 93% (geometric mean: 94%) reduction in worm burden superior to rPMY vaccination, results using the latter are promising and show the potential for further development of a recombinant PMY-based vaccine against the bovine lungworm.
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hanover, Germany. christina.strube@tiho-hannover.de.
authors.forename: Christina
authors.initials: C
authors.lastname: Strube
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hanover, Germany. claas.haake@tiho-hannover.de.
authors.forename: Claas
authors.initials: C
authors.lastname: Haake
authors.affiliation: Novartis Centre de Recherche Santé Animale, St. Aubin, Switzerland. heinz.sager@novartis.com.
authors.forename: Heinz
authors.initials: H
authors.lastname: Sager
authors.affiliation: Novartis Centre de Recherche Santé Animale, St. Aubin, Switzerland. sandra.schorderet_weber@novartis.com.
authors.forename: Sandra
authors.initials: S
authors.lastname: Schorderet Weber
authors.affiliation: Novartis Centre de Recherche Santé Animale, St. Aubin, Switzerland. ronald.kaminsky@novartis.com.
authors.forename: Ronald
authors.initials: R
authors.lastname: Kaminsky
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hanover, Germany. sandra.buschbaum@tiho-hannover.de.
authors.forename: Sandra
authors.initials: S
authors.lastname: Buschbaum
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hanover, Germany. deborah.joekel@tiho-hannover.de.
authors.forename: Deborah
authors.initials: D
authors.lastname: Joekel
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hanover, Germany. sabine.schicht@tiho-hannover.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schicht
authors.affiliation: Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Molecular Immunology, Munich, Germany. kremmer@helmholtz-muenchen.de.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kremmer
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hanover, Germany. julia.korrell@tiho-hannover.de.
authors.forename: Julia
authors.initials: J
authors.lastname: Korrell
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hanover, Germany. christina.strube@tiho-hannover.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schnieder
authors.affiliation: Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany. gvsamson@fu-berlin.de.
authors.forename: Georg
authors.initials: G
authors.lastname: von Samson-Himmelstjerna
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology*; D000947:Antigens, Helminth / Q000276:immunology*; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control*; D004021:Dictyocaulus / Q000276:immunology* / Q000502:physiology; D004022:Dictyocaulus Infections / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control*; D005260:Female; D007814:Larva; D008297:Male; D014335:Tropomyosin / Q000276:immunology*; D014611:Vaccination / Q000662:veterinary*
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D014335:Tropomyosin