A different approach to increase immunogenicity of eM2 was described by other groups. Constructs composed of four tandem copies of the eM2 peptide fused to flagellin, a ligand of TLR5 (Toll-like receptor 5) [41], or glutathione-S-transferase fusion protein bearing various numbers of eM2 epitope copies [42], were used as immunogens. These studies showed that high eM2 epitope densities in a single recombinant protein molecule resulted in enhanced eM2-specific humoral response and higher survival rates of infected animals.