Immunopathogenesis of Campylobacter jejuniinfection in a small animal model

Abstract

Abstract We set out to develop and characterize a small animal model of Campylobacter jejuni(CJ) infection that recapitulates human campylobacteriosis. Adult C57BL/6J mice are rendered susceptible to colonization and disease by pre-treatment with a zinc deficient diet and a broad-spectrum antibiotic cocktail. We have established this model with four strains with diverse capsular serotypes and flagellar groups, two key virulence factors for CJ pathogenesis. We measured colonization, weight loss, diarrhea, fecal inflammatory markers, and cytokine production by mesenteric lymphocytes and splenocytes. Diarrhea containing visible mucous and/or blood and degree of weight loss vary in severity depending on the strain and dose. Interestingly, we identified an inverse relationship between inoculum dose and levels of fecal inflammatory markers, with lower inoculum doses inducing significantly higher inflammation. We also observed production of IFNγ and IL-17 at day 9 post infection and despite no decrease in CJ colonization, IFNγ and IL-17 levels decreased by day 21 with a subsequent increase in IL-10 production. We also observed higher levels of IFNγ and IL-17 in mice challenged with strain CG8486 relative to those challenged with strain 81–176 pointing to potential strain differences. These differences observed were more striking in mesenteric lymphocytes versus splenocytes, indicating that local cellular responses differed from systemic responses. We have developed a model of inflammatory diarrhea in adult mice that exhibits hallmarks of CJ infection and further identified significant shifts in cytokine expression associated with the duration of infection, bacterial strain utilized, and therapeutic treatment. Research reported in this presentation is supported by Navy work unit number: 6000.RAD1.DA3.A0308 and CARB-X. CARB-X’s funding for this project is sponsored by the Cooperative Agreement Number IDSEP160030 from ASPR/BARDA and by awards from Wellcome Trust, the UK Global Antimicrobial Resistance Innovation Fund (GAMRIF) funded by the UK Government Department of Health and Social Care (DHSC) and the Bill & Melinda Gates Foundation. The content is solely the responsibility of the authors and does not necessarily represent the official views of CARB-X or any of its funders. Disclaimers: The views expressed in this work are those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S. Government. F. Poly is an employee of the U.S. Government. This work was prepared as part of official duties. Title 17 U.S.C. §105 provides that ‘Copyright protection under this title is not available for any work of the United States Government.’ Title 17 U.S.C. §101 defines a U.S. Government work as a work prepared by a military service member or employee of the U.S. Government as part of that person’s official duties.The animal study protocol was reviewed and approved by the Naval Medical Research Center IACUC in compliance with all applicable Federal regulations governing the protection of animals in research.