A Protein Subunit Filovirus Vaccine Facilitates Maternal Immunization in Mice

Abstract

Abstract Ebola virus disease (EVD) is highly pathogenic and virulent and has caused large scale outbreaks in Central and West Africa. To date there are no known correlates of protection however, recently the FDA and EMA have approved a vaccine, Ervebo. This vaccine utilizes a replication competent viral vector which may be contraindicated in immunocompromised individuals, pregnant women, and infants. Our lab has developed a recombinant protein subunit vaccine, a platform that is generally considered safe for immunocompromised, pregnant women, and infants. Our vaccine, when properly adjuvanted, demonstrates protection in non-human primates and may also induce maternal immunization. Maternal Immunization is the phenomena of inducing passive immunity via maternal antibody. This occurs via transfer of IgG using the FcRn. This receptor binds the Fc portion of IgG in a pH dependent manner which facilitates transcytosis of IgG across the placental, mammary tissue, as well as gut epithelial layer. In rodents, maternal IgG is transferred across the gut epithelia throughout the nursing period. This project demonstrates in mice the immunogenicity of a protein subunit vaccine comprised of Ebola glycoprotein and adjuvant administered during gestation as well as the transfer of antigen specific maternal antibody to offspring through milk. To investigate maternal immunization we vaccinated female Swiss Webster mice during gestation and measured antigen specific IgG levels in both the mothers and pups as well as in the milk. Antigen specific maternal antibody titers found in pup sera mimic those found in fully immunized adult females weeks after weaning, indicating the potential for maintaining an antigen specific humoral response in neonates.