Cutting-Edge Approaches Toward Novel and Cross-Protective Influenza Vaccines

Abstract

The currently available vaccines against influenza are seasonal, viral strain specific, and hence, their efficacy is limited when the circulating strain is not the one included in them. We describe herewith some of the novel approaches for developing influenza vaccines, in particular peptide- or epitope-based vaccines. A discussion of the epitope-based approach is provided, emphasizing its limitations and advantages, as well as a detailed description of the known influenza epitopes. Finally, we describe our own approach for the design of an epitope-based broad-spectrum “universal” flu vaccine for human use, which is comprised of a synthetic protein expressing multiple copies of nine different conserved epitopes of influenza proteins. These epitopes are common to the vast majority of influenza virus strains regardless of their antigenic drifts and shifts. The vaccine, activating both the humoral and cellular arms of the immune response in both animal models and humans, is presently in phase II clinical trials and is expected to confer cross-strain immunity and to protect also against future strains of the influenza virus.