Submitted to: American Society for Microbiology
Publication Type: Abstract only
Publication Acceptance Date: 6/29/2006
Publication Date: 9/9/2006
Citation: He, H., Genovese, K.J., Swaggerty, C.L., Kogut, M.H. 2006. Prophylactic application of immune stimulatory CpG-ODN reduces Salmonella enterica subsp. Arizonae organ colonization and mortality in young turkeys [abstract]. American Society for Microbiology. p. 67. Interpretive Summary:
Technical Abstract: Synthetic oligodeoxynucleotides (ODN) containing CpG dinucleotides (CpG-ODN) mimics bacterial DNA and are stimulatory to innate immune system in most vertebrate species through Toll-like receptor 9. The immunostimulatory activities of CpG-ODN have been studied extensively and are well characterized in human and murine immune cells. However, information on immune responses of avian species to CpG-ODN is limited. The immune stimulatory activity of CpG-ODN has not been studied in turkeys, an important species in the poultry industry. Here, we have evaluated the effects of various CpG ODNs on the innate immune functions of turkey immune cells, including degranulation and respiratory burst in the heterophils and nitric oxide (NO) production in the monocytes. Our results indicate that CpG-ODNs do not stimulate significant degranulation and respiratory burst activities in the turkey heterophils. However, many CpG-ODNs have shown great stimulatory effects (more potent than bacterial lipopolysaccharide) on NO production in the turkey monocytes. The optimal CpG-ODN for inducing NO production in the monocytes is the one containing GTCGTT motif. Based on these results, we conducted additional experiments to test the hypothesis that immune stimulatory CpG-ODN may increase resistance to bacterial infection in the young turkeys by stimulating their innate immunity. In this study, the newly hatched turkeys, obtained from a commercial source, were given CpG-ODNs or a control ODN that does not contain CpG motif at 50 µg/bird via intra-peritoneal (i.p.) injection. Twenty-four hours after the CpG-ODN treatments, turkeys were challenged with live Salmonella enterica subsp. Arizonae (SEA) (suspended in PBS). For the organ colonization experiment, 0.5-1x10**7 cfu/bird was given orally to the turkeys. For the mortality experiment, 0.5-1x1O**7 cfu/bird was given to the turkey via i.p. injection. Twenty-four hours after the oral SEA challenge, birds were euthanized with CO2 and liver and spleen were aseptically removed from each bird and cultured for the organ colonization of SEA. The mortality was monitored for a period of 7 days after i.p. SEA challenge. A significant reduction (p<0.05) of organ invasion by SEA was observed in turkeys pretreated with CpG-ODNs containing the immunostimulatory GTCGTT motif. These CpG-ODNs also significantly reduced mortality of turkeys with acute peritoneal infection of SEA. Our study provides evidence that immunostimulatory CpG-ODN stimulated innate immune activities and enhanced the resistance to infectious pathogens in neonatal turkeys.