A M2 protein-based universal influenza vaccine containing Advax-SM adjuvant provides newborn protection via maternal or neonatal immunization

Vaccine. 2021 Aug 23;39(36):5162-5172. doi: 10.1016/j.vaccine.2021.07.037. Epub 2021 Aug 3.

Abstract

Background: Despite newborns being at increased risk of serious influenza infection, influenza vaccines are currently not recommended for use in infants under 6 months of age. We therefore sought to evaluate the protective efficacy in mice of an M2-based influenza vaccine (CapM2e) formulated with Advax-SM adjuvant. Vaccine protection was assessed via both passive maternal immunization and direct neonatal immunization.

Methods: For maternal transfer studies, female mice were immunized 1 week before and after mating. Blood was collected from both mother and offspring during weaning and pups were challenged when they reached 3 weeks of age with lethal doses of H1N1 and homologous reassortment influenza strain H3N2 with conserved M2. For direct immunization studies, newborns were immunized at 1 and 3 weeks of age and blood was collected prior to challenge at 4 weeks of age.

Results: Maternal immunization with CapM2e + Advax-SM vaccine induced high maternal M2e antibody levels that were passively transferred to their offspring and provided them with protection against both H1N1 and H3N2 influenza strains when challenged at 3 weeks of age. When used for direct immunization of neonatal mice, CapM2e + Advax-SM vaccine similarly induced high serum M2e antibody levels and protected against H1N1 and H3N2 influenza challenges with protection associated with inhibition of virus replication with a significant reduction in lung virus load in immunized pups.

Conclusion: CapM2e + Advax-SM vaccine could be useful for protecting newborns against diverse influenza A strains, with opportunities to achieve protection by passive maternal immunization or active neonatal immunization. This data supports further development of this promising M2e-based vaccine candidate.

Keywords: Adjuvant; Advax; Influenza; Maternal; Neonatal; Vaccine.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Viral
  • Female
  • Immunization
  • Influenza A Virus, H1N1 Subtype*
  • Influenza A Virus, H3N2 Subtype
  • Influenza Vaccines*
  • Inulin / analogs & derivatives
  • Mice
  • Mice, Inbred BALB C
  • Orthomyxoviridae Infections* / prevention & control
  • Viral Matrix Proteins

Substances

  • Antibodies, Viral
  • Influenza Vaccines
  • Viral Matrix Proteins
  • delta inulin
  • Inulin