title: Efficient immunocastration of male piglets by immunoneutralization of GnRH using a new GnRH-like peptide.
abstract: Active immunization to immunomodulate regulatory processes suffers from the disadvantage that the antigen is usually 'self' and therefore poorly immunogenic. This has been well illustrated by the long-standing experience with immunocastration vaccines targeting GnRH, a ten amino acid peptide. Not all animals vaccinated with these vaccines are equally affected, even after multiple vaccinations. This is a severe handicap when immunocastration vaccines are applied to male piglets to circumvent surgical castration. Surgical castration is universally practised to prevent boar taint, produced in the testicles of mature boars. Alternative immunocastration is only acceptable if all animals are equally affected using a minimum of vaccinations. Vaccines based on the GnRH peptide itself cannot meet these goals. We showed that using a GnRH-like peptide, a 20 amino acid tandem repeat of the amino acid sequence of the GnRH peptide, these goals can be attained. Using the tandem GnRH peptide to vaccinate male piglets completely abolished the development and endocrinological functioning of the testicles, in contrast to monomer GnRH. These results show that superior antigens can be made for effective immunomodulation by appropriate alteration of the antigen.
authors.affiliation: Central Veterinary Institute (CDI-DLO), Lelystad, The Netherlands.
authors.forename: R H
authors.initials: RH
authors.lastname: Meloen
authors.forename: J A
authors.initials: JA
authors.lastname: Turkstra
authors.forename: H
authors.initials: H
authors.lastname: Lankhof
authors.forename: W C
authors.initials: WC
authors.lastname: Puijk
authors.forename: W M
authors.initials: WM
authors.lastname: Schaaper
authors.forename: G
authors.initials: G
authors.lastname: Dijkstra
authors.forename: C J
authors.initials: CJ
authors.lastname: Wensing
authors.forename: R B
authors.initials: RB
authors.lastname: Oonk
mesh_terms: D000276:Adjuvants, Immunologic; D000595:Amino Acid Sequence; D000736:Androstenes / Q000378:metabolism; D000818:Animals; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000276:immunology*; D006433:Hemocyanins / Q000276:immunology; D008297:Male; D008969:Molecular Sequence Data; D009919:Orchiectomy / Q000379:methods / Q000662:veterinary*; D010455:Peptides / Q000276:immunology; D013552:Swine / Q000097:blood / Q000276:immunology / Q000502:physiology*; D013737:Testis / Q000276:immunology* / Q000473:pathology; D013739:Testosterone / Q000097:blood; D014611:Vaccination / Q000662:veterinary*; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000736:Androstenes; D010455:Peptides; D014614:Vaccines, Synthetic; C000214:androst-16-en-3-one; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin