Leukocyte response to Campylobacter intra-abdominal infection in one day old leghorn chickens

Authors: Genovese, Kenneth - Ken; He, Louis; Swaggerty, Christina - Christi; Byrd Ii, James - Allen; Kogut, Michael - Mike

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2023
Publication Date: 2/28/2023
Citation: Genovese, K.J., He, H., Swaggerty, C.L., Byrd II, J.A., Kogut, M.H. 2023. Leukocyte response to Campylobacter intra-abdominal infection in one day old leghorn chickens. Microorganisms. 11(3). Article 613. https://doi.org/10.3390/microorganisms11030613.
DOI: https://doi.org/10.3390/microorganisms11030613

Interpretive Summary: Campylobacter has long been viewed as a normal flora bacteria in the chicken. The purpose of this study was to determine if Campylobacter induced an immune response in chickens when injected into their abdominal cavity. The data shows that Campylobacter does induce an immune response in chickens, causing increased numbers of white blood cells both in the peripheral circulation and at the site of infection. However, the response to Campylobacter was less than the response associated with Salmonella injection. These studies suggest that developing intervention strategies that use the chicken's immune system to fight Campylobacter infections may assist in reducing foodborne illness due to Campylobacter contamination.

Technical Abstract: Using a laboratory model of Salmonella intra-abdominal challenge in chickens, we have developed a model for the study of the chicken's immune response to a Campylobacter intra-abdominal challenge. The intra-abdominal Campylobacter infection model facilitates the characterization of peripheral blood leukocyte dynamics and abdominal cell infiltrates. Day-of-hatch leghorn chickens were injected intra-abdominally with Campylobacter jejuni [(CJ)1 x108 colony-forming units (CFUs)]. Changes in peripheral blood leukocyte numbers and abdominal cell infiltrates were monitored at 0, 4, 8, and 24 hours post-injection. Peripheral blood leukocyte numbers were also determined for 2 hours post- injection. In mortality studies, birds were injected intra-abdominally with 1 x108 CFUs CJ and mortalities were recorded for 72 hours post-injection. In the peripheral blood of CJ-injected chicks, total white blood cell (WBC) numbers began increasing by 2 hours post-injection, peaking at 4 hours post-injection, with the predominant cell type being polymorphonuclear leukocytes (heterophils). Total WBCs declined after 8 hours and this decline continued at 24 hours, with total WBC numbers approaching control values. Injection of CJ into the abdominal cavity caused a rapid rise in abdominal cell infiltrates, with the predominant infiltrating leukocytes being heterophils. Peak abdominal heterophil infiltrates were observed at 8 hours post-injection, declining only slightly by 24 hours post-injection. In mortality studies, mortality in the CJ challenge groups reached 30%. Mortality in the Salmonella enteritidis positive control groups were greater than 50%. The data suggest that Campylobacter infection does stimulate the innate immune response in chickens, however, the immune response and infection is not characterized with the high levels of mortality observed with a Salmonella infection. The data provides a basis for the study and characterization of the chicken's immune response to Campylobacter and the possible development of intervention strategies to prevent the infection and colonization of poultry.