Development of a cytotoxic T-lymphocyte-based, broadly protective influenza vaccine.

The current vaccination strategy against influenza is to induce production of antibodies directed against the surface antigens of these viruses. However, frequent changes in the surface antigens of influenza viruses allow them to avoid antibody-mediated immunity. On the other hand, it is known that cytotoxic T-lymphocyte (CTL) populations directed against internal antigens of influenza A virus are broadly cross-reactive to influenza virus subtypes. The present authors have previously demonstrated that antigens chemically coupled to the surface of liposomes made using unsaturated fatty acids are cross-presented by APCs via MHC class I to CD8(+) T cells and induce antigen-specific CTLs. Based on this finding, a liposome vaccine that is capable of inducing CTL response against internal antigens of influenza viruses and removing virus-infected cells in the host has been developed. The CTL-based liposomal technique might be applicable for developing vaccines against influenza and other viruses, such as hepatitis C, HIV, and severe acute respiratory syndrome corona virus, which frequently change their surface antigenic molecules.