title: Immunization routes in cattle impact the levels and neutralizing capacity of antibodies induced against S. aureus immune evasion proteins.
abstract: Vaccines against S. aureus bovine mastitis are scarce and show limited protection only. All currently available vaccines are applied via the parenteral (usually intramuscular) route. It is unknown, however, whether this route is the most suitable to specifically increase intramammary immunity to combat S. aureus at the site of infection. Hence, in the present study, immunization via mucosal (intranasal; IN), intramuscular (triangle of the neck; IM), intramammary (IMM) and subcutaneous (suspensory ligament; SC) routes were analyzed for their effects on the quantity of the antibody responses in serum and milk as well as the neutralizing capacity of the antibodies within serum. The experimental vaccine comprised the recombinant S. aureus immune evasion proteins extracellular fibrinogen-binding protein (Efb) and the leukotoxin subunit LukM in an oil-in-water adjuvant combined with a hydrogel and alginate. The highest titer increases for both Efb and LukM specific IgG1 and IgG2 antibody levels in serum and milk were observed following SC/SC immunizations. Furthermore, the harmful effects of Efb and leukotoxin LukMF' on host-defense were neutralized by serum antibodies in a route-dependent manner. SC/SC immunization resulted in a significant increase in the neutralizing capacity of serum antibodies towards Efb and LukMF', shown by increased phagocytosis of S. aureus and increased viability of bovine leukocytes. Therefore, a SC immunization route should be considered when aiming to optimize humoral immunity against S. aureus mastitis in cattle.
authors.affiliation: Ruminant Research and Development, MSD Animal Health, Wim de Körverstraat 35, 5830, AA, Boxmeer, The Netherlands. eveline.boerhout@merck.com.|Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584, CL, Utrecht, The Netherlands. eveline.boerhout@merck.com.
authors.forename: Eveline
authors.initials: E
authors.lastname: Boerhout
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584, CL, Utrecht, The Netherlands. m.vrieling@uu.nl.|Department of Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584, CX, Utrecht, The Netherlands. m.vrieling@uu.nl.
authors.forename: Manouk
authors.initials: M
authors.lastname: Vrieling
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584, CL, Utrecht, The Netherlands. l.benedictus1@uu.nl.
authors.forename: Lindert
authors.initials: L
authors.lastname: Benedictus
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584, CL, Utrecht, The Netherlands. a.j.j.m.daemen@uu.nl.
authors.forename: Ineke
authors.initials: I
authors.lastname: Daemen
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584, CL, Utrecht, The Netherlands. l.ravesloot@uu.nl.
authors.forename: Lars
authors.initials: L
authors.lastname: Ravesloot
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584, CL, Utrecht, The Netherlands. v.rutten@uu.nl.|Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa. v.rutten@uu.nl.
authors.forename: Victor
authors.initials: V
authors.lastname: Rutten
authors.affiliation: Ruminant Research and Development, MSD Animal Health, Wim de Körverstraat 35, 5830, AA, Boxmeer, The Netherlands. piet.nuijten@merck.com.
authors.forename: Piet
authors.initials: P
authors.lastname: Nuijten
authors.affiliation: Department of Medical Microbiology, University Medical Center Utrecht, PO G04.614, Heidelberglaan 100, 3584, CX, Utrecht, The Netherlands. j.vanstrijp@umcutrecht.nl.
authors.forename: Jos
authors.initials: J
authors.lastname: van Strijp
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584, CL, Utrecht, The Netherlands. a.p.koets@uu.nl.|Department of Bacteriology and TSE, Central Veterinary Institute part of Wageningen UR, Edelhertweg 15, PO box 65, 8200, AB, Lelystad, The Netherlands. a.p.koets@uu.nl.
authors.forename: Ad
authors.initials: A
authors.lastname: Koets
authors.affiliation: Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 7, 3584, CL, Utrecht, The Netherlands. s.w.f.eisenberg@uu.nl.
authors.forename: Susanne
authors.initials: S
authors.lastname: Eisenberg
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000378:metabolism*; D001426:Bacterial Proteins / Q000276:immunology; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D005260:Female; D007114:Immunization / Q000379:methods*; D008414:Mastitis, Bovine / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D008892:Milk / Q000737:chemistry; D013203:Staphylococcal Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D013209:Staphylococcal Vaccines / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; C114014:Efb protein, Staphylococcus aureus; C091659:LukM protein, Staphylococcus aureus; D013209:Staphylococcal Vaccines; D014614:Vaccines, Synthetic