Abstracts / Veterinary Immunology and Immunopathology 128 (2009) 211–347 323 were less obvious than what has been observed for human cells. These observations further stress the presence of Species differences in ODN-induced responses. doi:10.1016/j.vetimm.2008.10.240 Inactivated parapoxvirus ovis as an immunomodulator in foals Cormac C. Breathnach * , David W. Horohov Department of Veterinary Science, Gluck Equine Research Cen- ter, University of Kentucky, Lexington, KY 40546-0099, United States Keywords: Horse; Immunomodulator; Immunostimulant; Interferon gamma E-mail address: cormac@uky.edu (C.C. Breathnach). Species: Equine Reduced IFN production is a characteristic of neona- tal foal immunodeficiency. It indicates decreased cellular immune function and explains the increased susceptibility of foals to intracellular pathogens such as Rhodococcus equi, whose clearance is heavily dependent on IFN-mediated effects. Therefore, safe augmentation of foal IFN produc- tion is critical to protect foals from infectious disease. Inac- tivated parapoxvirus ovis (iPPVO) is a known immunomod- ulator marketed for use in horses. This study tested the ability of commercial iPPVO to elevate foal IFN production in vitro and in vivo. PBMC were prepared at regular intervals from 6 pony foals and cultured in the presence of medium alone, iPPVO or Con A for 72 h. All samples were then pulsed with PMA and ionomycin in the presence of brefeldin A for 4 h to promote intracellular accumulation of IFN and TNF for their subsequent detection by flow cytometry. Also, PBMC cultured with iPPVO or Con A for 24 h were tested for altered cytokine gene expression by real-time PCR. Notably, foal PBMC cultured with iPPVO, but not with Con A, demon- strated increased IFN production following PMA and ion- omycin pulse. This indicates that iPPVO increases the IFN- producing ability of foal PBMC. To investigate whether treatment with iPPVO has a similar effect in vivo, 20 pony foals were divided into 3 groups. Group 1 foals (n = 6) received saline i.m. (0.9% NaCl) on days 0, 2 and 9. Group 2 foals (n = 7) received iPPVO i.m. on days 0, 2 and 9. Group 3 foals (n = 7) received iPPVO i.m. on day 0 only. All foals were less than 10 days of age on day 0 of the study. PBMC sam- ples prepared from each foal at regular intervals through 6 months of age were stimulated with PMA and ionomycin to measure intracellular IFN production. Serial whole blood RNA samples were also prepared to measure the effects of iPPVO treatment on ex vivo cytokine gene expression. Treatment of young foals with iPPVO following label rec- ommendations did not significantly alter their ability to produce IFN. However, the above in vitro data confirm that iPPVO does increase the IFN producing capacity of foal PBMC. Varying dosage and route of administration of iPPVO will be pursued to reproduce this effect in vivo. doi:10.1016/j.vetimm.2008.10.241 IL-18 receptor induction by IL-12 in the chicken: IL-12 and IL-18 synergistically stimulate IFN- production Jesse D. Thomas 1,2,3,* , Dale I. Godfrey 2 , John W. Lowenthal 1 , Andrew G.D. Bean 1 1 CSIRO Livestock Industries, AAHL, Geelong, Australia 2 University of Melbourne, Melbourne, Australia 3 Australian Poultry CRC, Australia Keywords: Interleukin (IL)-12; IL-18; Interferon (IFN) gamma; IL-18 receptor E-mail address: jesse.thomas@csiro.au (J.D. Thomas). Species: Avian The control of viral infections is of critical importance to poultry industries worldwide and this is highlighted by costly infection outbreaks such as Avian Influenza. Currently, increasingly hyper-virulent viral strains are becoming more apparent and therefore new vaccine and anti-viral strategies are required to ameliorate the impact of these infections. To develop these improved strategies a greater understanding of the anti-viral response is criti- cal. In the chicken, evidence is still being gathered on the existence of a defined Th1 and Th2 immune response, how- ever, support for the theory of this dichotomous response is growing rapidly. Following the release of the full chicken genome sequence in 2004, many immune genes identi- fied were similar to those seen in the mammalian system. Now a clearer picture is available of how a dichoto- mous immune response in the chicken could have evolved similarly in function and in structure to its mammalian counterpart. This information provides new avenues for targeting therapies towards increasingly hyper-virulent infectious agents. Predominantly, anti-viral strategies tar- get and modulate various aspects of the Th1 arm of the immune response. In the mammalian system, the innate phase of the Th1 response is characterised by cytokines IL-12 and IL-18, acting in synergy, to up-regulate the expres- sion of IL-18 and IL-12 receptors, respectively. It is this important interaction during a viral response that induces the production of the key anti-viral protein IFN-. This response process is a characteristic sequence of interac- tions and events identified in cell mediated immunity in mammals. In this study, we investigated the status of the ChIL-18R and ChIFN- following stimulation with E. coli expressed recombinant cytokines ChIL-12 and ChIL- 18. It was found that following 48–72h incubation of chicken splenocytes with ChIL-12 there was significant up- regulation of ChIL-18R mRNA. Using this information, we investigated if this ChIL-12 induced ChIL-18R expression showed downstream functionality in the presence of ChIL- 18. We found that pre-treating chicken splenocytes with ChIL-12 for 48–72 h followed by a 24–48 h incubation with ChIL-18 induced up-regulation of ChIFN- production in a dose-dependant manner relative to single and multiple cytokine controls. This provides further evidence for the conservation of a Th1-like system in a non-mammalian (avian) Species. These findings could provide potential new target areas for strategies towards the production of therapeutics and anti-viral agents against increas-