Development of a novel dual-domain nanoparticle antigen construct for universal influenza vaccine

Abstract

A highly effective antigen construct for presenting conserved antigen domains is essential to the development of a universal influenza vaccine. We have developed a novel dual-domain nanoparticle fusion protein (DDNFP) which allows independent presentation of two conserved domains. The conserved domains used were from two separate viral surface proteins, M2e of M2 and fusion peptide (FP) or long alpha helix (CD) of HA2. The carrier is a novel nanoparticle protein - the dodecameric DNA binding protein from starved cells (Dps) of bacteria or archaea. Dps was found to be uniquely capable of simultaneous fusion and surface presentation at both N- and C-termini while retaining the ability to form nanoparticles. Thus, DDNFPs with M2e and FP or CD fused at N- and C- termini of Dps from E. coli (EcDps) or other bacteria were first constructed based on the H1 subtype sequences along with corresponding single-domain nanoparticle fusion proteins (SDNFPs). They were expressed at high levels in bacteria and found to form nanoparticles of the expected size (~9 nm). They were stable against treatment at high temperatures. The DDNFPs (M2e-EcDps-FP and M2e-EcDps-CD) induced strong antibody responses against individual antigen domains and provided full protection against lethal challenge with PR8 virus (H1N1). Importantly, the protection by DDNFPs was synergistically enhanced as compared to SDNFPs. The M2e-EcDps-CD provided an even stronger protection than M2e-EcDps-FP and therefore appeared to be the superior construct. Together, with novel domain combination, enhanced protection and ease of production, this M2e/CD DDNFP could potentially be a highly effective antigen construct for the universal influenza vaccine.

An Improved Inactivated Influenza Vaccine with Enhanced Cross Protection

“…To further characterize low pH-induced HA structural changes, an anti-CD polyclonal antibody was used to react with treated influenza antigens. This specific antibody was generated in mice using the CD domain (H1 consensus) fused to a nanoparticle carrier protein ( 23 ). It has been shown to be protective against lethal challenge ( 23 ), thus confirming its ability in recognizing corresponding domains in native antigens.…”

“…For measurement of low pH-induced structural changes in HA, an ELISA (anti-CD ELISA) was performed with a mouse anti-CD polyclonal antibody (serum) which was generated with the CD domain of H1 subtype consensus sequence fused to a nanoparticle carrier (EcDps, DNA-binding protein from starved cells of bacteria from E. coli ) ( 23 ). Untreated and low pH-treated antigens were coated onto plates as described above.…”

“…The non-neutralizing antibodies against conserved domains have been increasingly recognized to play a significant role in cross protection via the antibody-dependent cytotoxicity (ADCC) ( 15 – 17 ). Various approaches are being evaluated to enhance immune responses against HA2 or HA stem, including chimeric HA ( 18 ), HA stem constructs ( 19 – 21 ), and selected HA2 domains including the CD or LAH ( 22 , 23 ). Based on exposure of the HA2 at low pH, inactivated antigens treated at pH 5.0 and 37°C have also been evaluated, but found to be incapable of inducing any increased cross-reactive antibody responses or increased cross protection ( 24 ).…”

H7 virus-like particles assembled by hemagglutinin containing H3N2 transmembrane domain and M1 induce broad homologous and heterologous protection in mice

“…In recent years, a great quantity of work had been carried out for the development of a ''universal" vaccine [29][30][31][32]. But the safety and efficacy of protection in vivo remain to be improved.…”

Progress in the Development of Universal Influenza Vaccines

“…The resultant nanoparticle vaccine display antigens on the surface of particles or enclose antigens in the particles in order to increase the antigenicity and immunogenicity of the vaccine. At present, research on nanoparticle universal influenza vaccines is mainly focused on virus-targeted proteins—e.g., HA, HA stem, M2e, NP, NA, and mosaic—which are synthesized into nanoparticles to increase the immune effect of the vaccine [ 81 , 82 , 83 , 84 , 85 , 86 , 87 ].…”