Comparison of antibody responses in mice generated by different multivalent Filovirus vaccines based on recombinant glycoprotein subunits

Abstract

Abstract Filoviruses cause fulminant hemorrhagic fevers with case-fatality rates up to 90%. Recombinant glycoprotein (GP) derived from Ebola virus (EBOV), Sudan virus (SUDV) and Marburg virus (MARV) have been expressed from stably transformed Drosophila S2 cells and used to formulate recombinant subunit vaccine candidates showing efficacy in rodents and non-human primates. Immunogenicity of 11 different formulations of our trivalent subunit vaccine with adjuvant was tested. Each group of Swiss Webster mice was administered a formulation with or without adjuvant. Mouse sera were collected two weeks after 2nd and 3rd vaccine doses and diluted 1:8,000 and 1:40,000 to determine titers of IgG binding to EBOV, SUDV and MARV GP by a microsphere immunoassay (MIA). MFI (median fluorescence intensity) was collected by Luminex xPonent software then graphed and statistically analyzed using GraphPad Prism. As expected, groups administered equal amounts of EBOV, SUDV, and MARV GP had the most balanced antibody response as compared to groups that did not receive equal amounts of GP. Formulations with optimal antigen doses generate balanced antigen-binding antibody responses. Additional experiments are ongoing including the characterization of virus neutralization activity of the different formulations.