title: Vaccination of rabbits with immunodominant antigens from Sarcoptes scabiei induced high levels of humoral responses and pro-inflammatory cytokines but confers limited protection.
abstract: Vaccination is an attractive ecological alternative to the use of acaricides for parasite control. However, effective anti-parasite vaccines against sarcoptic mange have not yet been developed. The purpose of this study was first to identify Sarcoptes scabiei immunodominant antigens and second to evaluate them as vaccine candidates in a rabbit/S. scabiei var. cuniculi model.
  
  
  
  The S. scabiei Ssλ15 immunodominant antigen was selected by immunoscreening of a S. scabiei var. hominis cDNA. The full-length cDNA was sequenced and cloned into the pGEX vector and the recombinant protein expressed in BL21 (DE3) cells and purified. A vaccination trial was performed consisting of a test group (n = 8) immunised with recAgs (a mix of two recombinant antigens, Ssλ15 and the previously described Ssλ20∆B3) and a control group (n = 8) immunised with PBS. All analyses were performed with R Statistical Environment with α set at 0.050.
  
  
  
  The full-length open reading frame of the 1,821 nt cloned cDNA encodes a 64 kDa polypeptide, the sequence of which had 96 % identity with a hypothetical protein of S. scabiei. Ssλ15 was localised by immunostaining of skin sections in the tegument surrounding the mouthparts and the coxa in the legs of mites. Rabbit immunisation with recAgs induced high levels of specific IgG (P < 0.010) and increased levels of total IgEs. However, no significant clinical protection against S. scabiei challenge was detected. Unexpectedly, the group immunised with the recAgs mix had significantly higher lesion scores (P = 0.050) although lower mean mite densities than those observed in the control group. These results might indicate that the lesions in the recAgs group were due not only to the mites density but also to an exacerbated immunological response after challenge, which is in agreement with the specific high levels of pro-inflammatory cytokines (IL-1 and TNFα) detected after challenge in this group.
  
  
  
  The selected antigens delivered as recombinant proteins had no clinical protective efficacy against S. scabiei infestation although immunisation reduced mite density. However, these results pave the way for future studies on alternative production systems, adjuvants, delivery methods and combinations of antigens in order to manage stimulation of clinical protective immune responses.
authors: Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de, Biotecnología Animal, La Olla-Deva, 33394, Asturias, Spain.
authors: Rosa
authors: R
authors: Casais
authors: Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Finca experimental La Mata, Programa de Investigación Forestal (PIF). Área de Cultivos Hortofrutícolas y Forestales, La Mata s/n, 33825, Asturias, Spain.
authors: Victor
authors: V
authors: Granda
authors: Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de, Biotecnología Animal, La Olla-Deva, 33394, Asturias, Spain.
authors: Ana
authors: A
authors: Balseiro
authors: Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de, Biotecnología Animal, La Olla-Deva, 33394, Asturias, Spain.
authors: Ana
authors: A
authors: Del Cerro
authors: Instituto Universitario de Biotecnología de Asturias, Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus El Cristo, Universidad de Oviedo, 33006, Oviedo, Spain.
authors: Kevin P
authors: KP
authors: Dalton
authors: Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de, Biotecnología Animal, La Olla-Deva, 33394, Asturias, Spain.
authors: Roxana
authors: R
authors: González
authors: Instituto Universitario de Biotecnología de Asturias, Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus El Cristo, Universidad de Oviedo, 33006, Oviedo, Spain.|Clinical Research Centre (CRC), Barts Health NHS Trust, 2 Newark Street, Abernethy Building, Whitechapel, London, UK.
authors: Pablo
authors: P
authors: Bravo
authors: Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de, Biotecnología Animal, La Olla-Deva, 33394, Asturias, Spain.
authors: J M
authors: JM
authors: Prieto
authors: Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, Bellaterra Cerdanyola del Vallès, Spain. maria.montoya@pirbright.ac.uk.|The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey, UK. maria.montoya@pirbright.ac.uk.
authors: Maria
authors: M
authors: Montoya
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D060829:Arthropod Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D016207:Cytokines / Q000276:immunology*; D005260:Female; D006801:Humans; D056724:Immunity, Humoral; D016056:Immunodominant Epitopes / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D011817:Rabbits; D012520:Sarcoptes scabiei / Q000235:genetics / Q000276:immunology*; D012532:Scabies / Q000276:immunology* / Q000469:parasitology / Q000517:prevention & control; D014611:Vaccination
chemical_list: D000906:Antibodies; D060829:Arthropod Proteins; D016207:Cytokines; D016056:Immunodominant Epitopes
keywords: Clinical protection; Immunodominant antigens; Sarcoptes scabiei; Sarcoptic mange; Vaccine candidates