2010 Annual Report 1a.Objectives (from AD-416) Evaluate swine influenza virus strain specific antigenic epitopes that might enable development of serological assays for pandemic H1N1 surveillance in swine. Evaluate selected antigenic epitopes and genetic factors of swine influenza virus that may lead to heterologous immunity elicited by influenza vaccines to enable development of improved vaccines with broader protective immunity against novel emerging influenza strains. 1b.Approach (from AD-416) Conduct immunological investigations of influenza A virus components that lead to immune responses against specific epitopes that may enable serological surveillance for the 2009 A/H1N1 in swine and determine whether heterologous immunity against endemic swine influenza viruses interferes with serological surveillance methods. Collaborate in conducting animal studies to determine the pathogenesis and transmissibility of selected isolates of the wild-type novel A/HINI virus from animals and correlate with genetic and antigenic changes. 3.Progress Report Initial project planning, experimental designs and a pilot study were completed investigating how a swine influenza A virus vaccine may lead to heterologous immunity against the 2009 A/H1N1 pandemic virus. The initial study detected heterologous immunity against the pandemic virus as a result of vaccination with an endemic swine influenza virus. A manuscript describing these findings has been prepared for publication in a peer-reviewed journal. Additional research is planned to identify the nature of this heterologous immunity and how it might interfere with serological surveillance. Research on serological responses to specific epitopes of the 2009 A/H1N1 pandemic virus is planned for FY11. Methods used for monitoring include phone contact, e-mail, and meetings.