1a. Objectives (from AD-416):
1. Conduct comparative immunology studies of avian species to determine variations in protective innate defense mechanisms to avian influenza infections. 2. Characterize humoral and cellular immune responses to avian influenza viruses and identify epitopes associated with immunity. 3. Develop immunological reagents and methodologies to evaluate vaccine efficacy and protection.
1b. Approach (from AD-416):
The project plan has three interrelated objectives that are designed to increase our basic understanding of the immunological response to avian influenza virus (AIV) infection in different avian species and will result in improved vaccine development. The first objectives initiate the characterization of host cytokine expression profiles from specific innate immune cells in vitro. These profiles will then be compared with cytokine profiles obtained from avian influenza (AI) infected tissues, in vivo, for a better understanding of the overall innate immune response to avian influenza viruses (AIV). Innate immune cells will be isolated or produced for in vitro analysis from multiple sources, including: specific pathogen-free (SPF) White Leghorn (egg laying-type), SPF White Plymouth Rock (meat-type) chickens, and SPF Small Beltsville White SPF turkeys from the Southeast Poultry Research Laboratory. In addition, some experiments will utilize commercial chickens, turkeys, geese, ducks or others as needed, as sources for primary cell culture. We have in-house supplies of SPF birds and eggs, which can be used for these studies. In addition, we also have access to major histocompatibility complex (MHC)-defined birds (Avian Disease Oncology Laboratory, East Lansing, MI) which can be used for immunogenetic comparison of cytokine responses within members of Gallus gallus species. Expected outcomes for this objective will be the determination of which cytokines and transcription factors contribute to a resistant phenotype of avian species to AIV. It may be likely that different profiles are determined for different bird species. Once innate immunity profiles have been established, the cellular and humoral immune responses that contribute to natural and vaccine-induced protection will be characterized. We will utilize chickens, turkeys, ducks and other bird species in these studies. Experiments in Objective 2 will determine antibody levels following infection and vaccination, identify cellular immune responses to homologous and heterologous AI isolates, and determine putative epitopes involved with immunity. We will specifically address: (1) the induction of anti-viral antibodies that correlates with protective efficacy, decreases in virus shedding, and provide cross-reactivity to homo- and heterosubtypic isolates, (2) the induction of cellular immunity in poultry and wild birds following infection or vaccination and challenge, (3) identify T-cell epitopes to the hemagglutinin and nucleoprotein proteins of AI. Finally, we will develop immunological reagents and methodologies to evaluate vaccine efficacy and protection. Besides the usual indicators of vaccine induced protection, including survival, or decreases in shedding, assays to determine why and how a particular vaccine induces immunological protection against challenge are lacking. By incorporating cytokines and toll-like receptor agonists into vaccine formulations, their contributions to humoral and cellular immunity can be evaluated. Finally, the extent of cross protective immunity developed in vaccinated birds will be examined by utilizing antigenic cartography.
3. Progress Report:
The Immunology project has been active both nationally and internationally to meet the objectives and milestones of the research project. Progress included; 1) the development of new techniques that allow isolation of individual cell types to examine how they immunologically react to avian influenza, 2) the protection of poultry from avian influenza through application of vaccines or anti-viral compounds, and 3) the study of antibody responses to avian influenza viruses and vaccines in different bird species. Collaborative research continues with national and international partners to continue to study the immune response of poultry to avian influenza. University partners include, but not limited to, the University of Georgia, the University of Delaware, the University of Arkansas, and the Ohio State University. Collaborative work with industry has included projects with CEVA Biomune, and Goldsboro Milling Company. Internationally, collaboration with the US Department of Agriculture, Office of International Research Programs and the All Russian Research Institute for Animal Health has continued to support the development of vaccines and immunology against avian influenza.
1. Different innate imune responses in duck following avian influenza infection. Domestic ducks are key intermediates in the transmission of H5N1 highly pathogenic avian influenza (HPAI) viruses, and therefore are included in vaccination programs to control H5N1 HPAI. Clear differences in response to infection and vaccination were demonstrated between the two most common domestic duck species, Pekin (Anas platyrhinchos domesticus) and Muscovy (Cairina moschata), with the Muscovy ducks presenting a more severe disease than the Pekin ducks and responding poorly to vaccination. These differences were in part explained by differences observed in the expression of innate immune related genes in the infected ducks. This information should be taken into account when developing effective vaccination programs for controlling H5N1 HPAI in different species of ducks.
2. Interferon alpha treatment protects chickens against highly pathogenic avian influenza (AI). Type I interferons, including interferon alpha, are naturally expressed after viral infection, and represent a first line of defense against AI. Following infection of chickens with avian influenza virus, transcription of interferon (IFN) alpha is quickly up regulated along with a myriad of other immune-related genes. In these studies, we assessed the protective potential of IFN alpha applied to birds prior to exposure to highly pathogenic AI. Intranasal application with IFN prior to and during active infection protected birds against morbidity and mortality. These studies demonstrate that in the absence of vaccination, birds can be protected against highly pathogenic AI.
3. Vaccine protection of turkeys against H5N1 highly pathogenic avian influenza (HPAI). In Southeast Asia, ongoing outbreaks of H5N1 HPAI remain a constant threat to poultry and human health due to its endemic nature. Current vaccines and vaccination strategies are currently being developed to protect birds and decrease transmission of these viruses. The objective of this study is to evaluate the efficacy of recombinant avian influenza vaccines (H5 subtype) in turkeys against challenge with a recent H5N1 isolate. Following challenge with a lethal dose of H5N1 HPAI, ninety-eight percent of turkeys receiving the recombinant AI vaccine survived. These results indicate this type of recombinant vaccine can be used as an aid during AI eradication efforts in this species of bird. This information will used by commercial poultry growers in the field as a tool to prevent avian influenza H5N1 in Southeast Asia.
Kapczynski, D.R., Martin, A., Haddad, E.E., King, D.J. 2012. Protection from clinical disease against three highly virulent strains of Newcastle disease virus after in ovo application of an antibody-antigen complex vaccine in maternal antibody-positive chickens. Avian Diseases. 56(3):555-560. DOI: 10.1637/9980-110311-Reg.1.