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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Immunol. | doi: 10.3389/fimmu.2019.02660

A novel live attenuated vaccine candidate protects against heterologous Senecavirus A challenge

  • 1Department of Veterinary and Biomedical Sciences, South Dakota State University, United States
  • 2Universidade Federal de Pelotas, Brazil
  • 3Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, United States
  • 4Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, United States

Senecavirus A (SVA) is an emerging picornavirus causing vesicular disease (VD) clinically indistinguishable from foot-and-mouth disease (FMD) in pigs. Notably, there are no vaccines currently available for SVA. Here we developed a recombinant SVA strain (rSVAm SacII) using reverse genetics and assessed its immunogenicity and protective efficacy in pigs. In vivo characterization of the rSVAm SacII strain demonstrated that the virus is attenuated, as evidenced by absence of lesions, decreased viremia and virus shedding in inoculated animals. Notably, while attenuated, rSVA mSacII virus retained its immunogenicity as high neutralizing antibody (NA) responses were detected in inoculated animals. To assess the immunogenicity and protective efficacy of rSVA mSacII, four-week-old piglets were sham-immunized or immunized with inactivated or live rSVA mSacII virus-based formulations. A single immunization with live rSVA mSacII virus via the intramuscular (IM) and intranasal (IN) routes resulted in robust NA responses with antibodies being detected around days 3-7 pi. Neutralizing antibody responses in animals immunized with the inactivated virus via the IM route were delayed and only detected after a booster on day 21 pi. Immunization with live virus resulted in recall T cell proliferation (CD4+, CD8+ and CD4+/CD8+ T cells), demonstrating efficient stimulation of cellular immunity. Notably, a single dose of the live attenuated vaccine candidate resulted in protection against heterologous SVA challenge, as demonstrated by absence of overt disease and reduced viremia, virus shedding and viral load in tissues. The live attenuated vaccine candidate developed here represents a promising alternative to prevent and control SVA in swine.

Keywords: Senecavirus A (SVA), Seneca Valley virus (SVV), Recombinant virus, live attenuated vaccine, Inactivated vaccine

Received: 27 Jul 2019; Accepted: 28 Oct 2019.

Copyright: © 2019 Sharma, Fernandes, De Lima, Joshi, Lawson and Diel. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Diego G. Diel, College of Veterinary Medicine, Cornell University, Department of Population Medicine and Diagnostic Sciences, Ithaca, United States, dgdiel@cornell.edu