Pilot-scale production of inactivated monoglycosylated split H1N1 influenza virus vaccine provides cross-strain protection against influenza viruses

Abstract

Influenza epidemics and pandemics caused by newly emerging virus strains highlight an urgent need to develop a universal vaccine against viruses. Previously, a monoglycosylated X-181_mg vaccine demonstrated that the HA possessing a single N-acetylglucosamine at each N-glycosylation site is superior to confer broader protection in mice than conventional vaccines. However, the greatest challenge in conducting clinical trials is the need to develop robust manufacturing processes capable of producing vaccines at the pilot scale with the desired stability, potency, and efficacy. Whether the monoglycosylated virus vaccine platform can be applied to the new vaccine strain in a timely manner and whether the mass-produced vaccine has the proper immunogenicity to induce cross-protective immunity remains unclear. Here, we show that a pilot-scale manufacturing process produced a monoglycosylated A/Brisbane/02/2018(H1N1) virus vaccine (IVR-190_mg) with a single glycan at each glycosylation site of HA and NA. Compared with the fully glycosylated virus vaccine (IVR-190_fg), the IVR-190_mg provided broader cross-protection in mice against a wide range of H1N1 variants. The enhanced antibody responses induced by IVR-190_mg immunization include higher hemagglutination-inhibition titers, higher neutralization activity, more anti-HA head domain, more anti-HA stem antibodies, higher neuraminidase activity inhibition titers, and notably, higher antibody-dependent cellular cytotoxicity. Additionally, the IVR-190_mg also induced a more balanced Th1/Th2 response and elicited broader splenic CD4⁺ and CD8⁺ T-cell responses than IVR-190_fg. This study demonstrated that IVR-190_mg produced using a pilot-scale manufacturing process elicits comprehensive cross-strain immune responses that have great potential to substantially mitigate the need for yearly reformulation of strain-specific inactivated vaccines.

Keywords: ADCC activity; Balanced B and T cell response; Cross-strain protection; HA head domain and HAstem antibodies; Monoglycosylated influenza vaccine; Monoglycosylated neuraminidase.