Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 9, 2007
Publication Date: May 2, 2007
Citation: He, H., Genovese, K.J., Swaggerty, C.L., Nisbet, D.J., Kogut, M.H. 2007. In vivo priming heterophil innate immune functions and increasing resistance to Salmonella enteritidis infection in neonatal chickens by immune stimulatory CpG-ODN oligodeoxynucleotides. Veterinary Immunology and Immunopathology. 117:275-283. Interpretive Summary: A chicken white blood cell called the heterophil can produce chemicals that kill bacteria. These bacteria-killing chemicals help chickens fight bacterial infections and stay healthy. DNA is a genetic blueprint of life and is present in all cells. DNA found in bacteria contains a unique element, called CpG-DNA. In test tubes, we have found that CpG-DNA can stimulate heterophils to produce more bacterial-killing chemicals. Here, we further investigated whether giving CpG-DNA to baby chicks can stimulate heterophils to produce more bacterial-killing chemicals and protect the chicks from infection by bacteria such as Salmonella. As a result, we found that CpG-DNA greatly enhances heterophils to produce bacterial-killing chemicals. Also, baby chickens that have received CpG-ODN had much less chance to have Salmonella living inside their body even with a heavy infection. This information is important to the pharmaceutical and poultry industries in the United States because it may offer a new method to produce healthy chickens and reduce the use of antibiotics.
Technical Abstract: Oligodeoxynucleotides (ODN) containing CpG dinucleotides (CpG-ODN) mimic bacterial DNA and stimulate the innate immune system of vertebrates. Here, we investigated the effects of intraperitoneal (ip) administered CpG-ODN on the innate immune functions of chicken heterophils. Our results demonstrated CpG-ODN-dependent priming of chicken heterophil degranulation and oxidative burst. Heterophils from chickens treated with CpG-ODN exhibited significantly higher (p<0.05) degranulation activity compared to PBS and control ODN (ODN containing no CpG motif) treated groups when stimulated with opsonized Salmonella enterica serovar enteritidis. Similarly, oxidative burst activity, which generates bactericidal reactive oxygen species, was significantly higher (p<0.05) in heterophils from the CpG-ODN treated group than from PBS and control ODN groups when stimulated with formalin-killed S. enteritidis. The priming effects of CpG-ODN on heterophil functions continued at least 4 days post treatments. In the infection study, newly hatched chickens were treated with CpG-ODN, control ODN or PBS for 24 h then challenged with oral inoculation of S. enteritidis. A significant reduction (p<0.05) in colonization of live and spleen by S. enteritidis was observed in chickens treated with CpG-ODN.