CD4 and influenza: The recombinant protein based on flagellin and theconserved antigens of two influenza proteins (M2e and aa 76–130 of ofHA2) combines the adjuvant activity of flagellin due to TLR5 recognition, ahighly conserved structure of M2e between human and avian influenza A virusstrains, and a conserved fragment of the second subunit of HA with B-cell, aswell as CD4+ and CD8+ T-cell epitopes.