Poster Presentation Lorne Infection and Immunity 2013

Analysis of inflammasome related molecules in the response to H5N1 Avian Influenza (#119)

Sarah J Fardy 1 2 , Simon Burggraaf 2 , Wayne G Kimpton 1 , John W Lowenthal 2 , Andrew G. D. Bean 2
  1. Melbourne University, Melbourne, Australia
  2. CSIRO, Geelong, VIC, Australia

Highly pathogenic avian influenza (HPAI) infection is extremely acute and associated with severe mortality in both humans and poultry. The rapid onset of disease suggests that virus-host interactions, such as the immune response to virus, might contribute to the severity. With this in mind, it is critical to understand the host-pathogen interactions in order to develop novel approaches to managing infection. Pro-inflammatory cytokines, such as interleukin (IL)-1β and IL18, are crucial to an anti-viral response, however, the control of the expression of these molecules is vital, as exacerbated levels can lead to deleterious outcomes. In mammals these cytokines are regulated by a complex cytoplasmic protein scaffold known as the Nalp3 inflammasome. Currently, the mechanisms for Nalp3 activation are largely unknown, however, it appears Nalp3 and the associated cleavage enzyme caspase 1 (ICE) are important regulators. To elucidate the role of the inflammasome in the chicken response to H5N1 HPAI, we identified and characterized chicken Nalp3, ICE, IL1β and IL18 and investigated their role during infection. Through qRT-PCR, siRNA gene knockdown and ELISA analysis, the chicken Nalp3 inflammasome has been identified and its role in the response to H5N1 HPAI analysed. All 4 genes are greatly upregulated, particularly Nalp3 and ICE. In tandem with this was increased IL1β and IL18 protein secretion, measured in chicken sera. Together, these data indicate a strong Nalp3 inflammasome response, following HPAI infection in the chicken. This work provides an insight into strategies that target the immune system for improving resistance to avian influenza.