Impact of LbSapSal Vaccine in Canine Immunological and Parasitological Features before and after Leishmania chagasi-Challenge

PLoS One. 2016 Aug 24;11(8):e0161169. doi: 10.1371/journal.pone.0161169. eCollection 2016.

Abstract

Dogs represent the most important domestic reservoir of L. chagasi (syn. L. infantum). A vaccine against canine visceral leishmaniasis (CVL) would be an important tool for decreasing the anxiety related to possible L. chagasi infection and for controlling human visceral leishmaniasis (VL). Because the sand fly salivary proteins are potent immunogens obligatorily co-deposited during transmission of Leishmania parasites, their inclusion in an anti-Leishmania vaccine has been investigated in past decades. We investigated the immunogenicity of the "LbSapSal" vaccine (L. braziliensis antigens, saponin as adjuvant, and Lutzomyia longipalpis salivary gland extract) in dogs at baseline (T0), during the post-vaccination protocol (T3rd) and after early (T90) and late (T885) times following L. chagasi-challenge. Our major data indicated that immunization with "LbSapSal" is able to induce biomarkers characterized by enhanced amounts of type I (tumor necrosis factor [TNF]-α, interleukin [IL]-12, interferon [IFN]-γ) cytokines and reduction in type II cytokines (IL-4 and TGF-β), even after experimental challenge. The establishment of a prominent pro-inflammatory immune response after "LbSapSal" immunization supported the increased levels of nitric oxide production, favoring a reduction in spleen parasitism (78.9%) and indicating long-lasting protection against L. chagasi infection. In conclusion, these results confirmed the hypothesis that the "LbSapSal" vaccination is a potential tool to control the Leishmania chagasi infection.

MeSH terms

  • Animals
  • Biomarkers
  • Brazil
  • Cytokines / metabolism
  • Dog Diseases / immunology*
  • Dog Diseases / metabolism
  • Dog Diseases / parasitology*
  • Dog Diseases / prevention & control
  • Dogs
  • Female
  • Inflammation Mediators / metabolism
  • Leishmania infantum / immunology*
  • Leishmaniasis Vaccines / administration & dosage
  • Leishmaniasis Vaccines / immunology*
  • Leishmaniasis, Visceral / veterinary*
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / metabolism
  • Male
  • Models, Biological
  • Nitric Oxide / biosynthesis
  • Parasite Load
  • Spleen / immunology
  • Spleen / parasitology
  • Vaccination

Substances

  • Biomarkers
  • Cytokines
  • Inflammation Mediators
  • Leishmaniasis Vaccines
  • Nitric Oxide

Grants and funding

Fundação de Amparo a Pesquisa do Estado de Minas Gerais, Brazil, grant CBB-APQ-02473-10/01225-11/01052-11/01698-12/02372-13, APQ-03576-13, CBB–PPM-00609-15: RCG. Fundação de Amparo a Pesquisa do Estado de Minas Gerais, Brazil, grant CBB-APQ-02007-12/02076-10/01225-11: DSL. Conselho Nacional de Desenvolvimento Científico e Tecnológico CNPq, Brazil, grant 482249/2012-9: RCG. Conselho Nacional de Desenvolvimento Científico e Tecnológico CNPq, Brazil, grant 480979/2013-8: DSL. RCO, OAMF, RTF, ABR, and RCG are grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico/CNPq and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/CAPES, Brazil, for fellowships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.