Influenza virus infection and the resulting complications are a significant global public health problem and understanding the overall immune response to infection will contribute to appropriate management of the disease and its potentially severe complications. Improving humoral immunity to influenza is the target of current conventional influenza vaccines, however, these are generally not cross-protective. On the contrary, cell-mediated immunity generated by primary influenza infection provides substantial protection against serologically distinct viruses due to recognition of cross-reactive T cell epitopes, often from internal viral proteins conserved between viral subtypes. Efforts are underway to develop a universal flu vaccine that would stimulate both the humoral and cellular immune responses leading to long-lived memory. Such a universal vaccine should target conserved influenza virus antibody and T cell epitopes that do not vary from strain to strain. The present invention incorporates immunoproteomics to uncover novel MHC class I specific epitopes derived from influenza-infected cells. These epitopes are conserved with epitope-specific CTLs cross-reacting against various different influenza strains. These epitopes have potential as new informational and diagnostic tools to characterize T cell immunity in influenza infection, and serves as a universal vaccine candidate complementary to current vaccines.
