DNA vaccine targeting the ectodomain of influenza M2 protein to endolysosome pathway enhances anti-M2e protective antibody response in mice

Abstract

A promising candidate for developing the universal influenza vaccine is the ectodomain of the M2 protein (M2e). We designed and prepared an experimental DNA vaccine with an improved potential to induce anti-M2e immune response. The sequence for truncated NS1 protein followed by 4xM2e was inserted into the expression vector pTriEx-4 (pEx). M2e repeats were fused to the transmembrane domain and cytoplasmic tail of lysosome-associated membrane glycoprotein 2 isoform A (LAMP-2a) to target the M2e to the endo-lysosome pathway, facilitating increased antigen presentation by MHC II. Using confocal microscope immunofluorescence analysis, we confirmed a strong colocalization of pEx 4M2e-LAMP-2a with early endosomes and a weaker colocalization with late endosomes. BALB/c mice immunized with three doses of pEx 4M2e-LAMP-2a DNA vaccine and challenged with 2LD 50 mouse-adapted influenza virus developed significantly (up to 16 times) higher anti-M2e antibody response in comparison to mice immunized with pEx 4M2e vaccine using the same immunization protocol. This was in correlation with the increased survival rate (near to 67% vs 50%) observed in animals immunized with pEx 4M2e-LAMP-2a DNA in comparison to mice immunized with pEx 4M2e.

Advances in Nucleic Acid Universal Influenza Vaccines

“…The article by Jaroslav Hollý et al described studies on M2e DNA vaccines and the results of the immunogenicity and protective properties of the vaccine were evaluated by administering the M2e DNA vaccine to BALB/c mice and performing viral challenge experiments, showing that the mice produced anti-M2e antibodies after vaccination with the M2e DNA vaccine. The survival rate of mice vaccinated with the M2e DNA vaccine was high after the viral challenge experiment [ 51 ]. Therefore, such studies indicated that the optimized M2e DNA vaccine could be a promising candidate for a universal influenza vaccine, inducing both humoral and cellular immune responses.…”