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ORIGINAL RESEARCH article

Front. Vet. Sci.
Sec. Veterinary Infectious Diseases
Volume 12 - 2025 | doi: 10.3389/fvets.2025.1518231
This article is part of the Research Topic The application of new technologies such as new vaccines, therapeutic cytokines and antibodies, and antiviral drugs in the prevention and treatment of animal infectious diseases View all 10 articles

The immunological and pathobiological properties of a novel live Salmonella Typhimurium-vectored Campylobacter vaccine candidate in layer chickens

Provisionally accepted
Robert J Moore Robert J Moore 1*Jamieson B Mcdonald Jamieson B Mcdonald 1Emily Gan Emily Gan 2Joel Cain Joel Cain 3Sapna G Thoduka Sapna G Thoduka 2Joseph Lee Joseph Lee 1Ben Wade Ben Wade 1Marta Mauri Marta Mauri 4Jon Cuccui Jon Cuccui 4Brendan Wren Brendan Wren 4Nicolle Hannah Packer Nicolle Hannah Packer 3Sarah Londrigan Sarah Londrigan 5Svenja Fritzlar Svenja Fritzlar 5Sameera Mohotti Sameera Mohotti 2Gregory J Underwood Gregory J Underwood 2Daniel M Andrews Daniel M Andrews 2Thi Thu Hao Van Thi Thu Hao Van 1
  • 1 RMIT University, Melbourne, Australia
  • 2 Bioproperties Pty Ltd, Bundoora, Australia
  • 3 Macquarie University, Sydney, New South Wales, Australia
  • 4 London School of Hygiene and Tropical Medicine, University of London, London, London, United Kingdom
  • 5 The University of Melbourne, Parkville, Victoria, Australia

The final, formatted version of the article will be published soon.

    Spotty Liver Disease (SLD) is a major economic and animal welfare threat to the global cage-free egg industry, which arises from the infection of layers with the emerging pathogen Campylobacter hepaticus. The occurrence of SLD can result in a significant decline in egg production and elevated mortalities. Currently, antibiotics are the most effective control measure, however, antibiotic resistance is an increasing global concern for public health, and there is a concerted effort to reduce antibiotic use in animal production. Poultry vaccination represents an alternative solution to reduce C. hepaticus levels in poultry. Autogenous vaccines are being used in some countries, with limited efficacy, but currently no vaccine is licensed for general use. This study developed, characterised, and evaluated the immunogenicity of a Salmonella Typhimurium bacterial strain used as a live vector to express and deliver the conserved Campylobacter N-glycan heptasaccharide as a target antigen against C. hepaticus. The replacement of the S. Typhimurium aroA gene with the Campylobacter pgl locus attenuated the vaccine strain and enabled conjugation of the heptasaccharide to S. Typhimurium endogenous lipopolysaccharide (LPS). Commercial layer hens vaccinated with the S. Typhimurium strain producing the Campylobacter heptasaccharide induced significantly increased IgY antibody titres specific to the Campylobacter heptasaccharide compared to birds vaccinated with the vector strain not expressing the heptasaccharide. Modification of the S. Typhimurium endogenous LPS with the heptasaccharide had no significant impact on IgY antibody responses raised against S. Typhimurium. This study provides evidence that the use of S. Typhimurium to deliver Campylobacter heptasaccharide can be a feasible approach to provide bi-valent immunogenicity against S. Typhimurium and C. hepaticus.

    Keywords: glycoconjugate, Vaccine, Salmonella typhimurium, Campylobacter hepaticus, Spotty liver disease, chicken, Live vaccine

    Received: 28 Oct 2024; Accepted: 03 Jan 2025.

    Copyright: © 2025 Moore, Mcdonald, Gan, Cain, Thoduka, Lee, Wade, Mauri, Cuccui, Wren, Packer, Londrigan, Fritzlar, Mohotti, Underwood, Andrews and Van. 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) or licensor 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: Robert J Moore, RMIT University, Melbourne, Australia

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.