RT Journal Article
SR Electronic
T1 A highly expressing, soluble, and stable plant-made IgG fusion carrying Zika virus envelope domain III elicits potent immunogenic responses in mice without adjuvant
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.07.13.199703
DO 10.1101/2020.07.13.199703
A1 Andrew G. Diamos
A1 Mary D. Pardhe
A1 Haiyan Sun
A1 Joseph G. L. Hunter
A1 Jacquelyn Kilbourne
A1 Qiang Chen
A1 Hugh S. Mason
YR 2020
UL http://biorxiv.org/content/early/2020/07/14/2020.07.13.199703.abstract
AB While therapeutics based on fusing a protein of interest to the IgG Fc domain have been enormously successful, fewer studies have investigated the vaccine potential of IgG fusions. In this study, we systematically compared the key properties of a panel of plant-made IgG fusion vaccine candidates targeting Zika virus envelope domain III (ZE3). Complement protein C1q binding of the IgG fusions was enhanced by: 1) ZE3 fusion to the IgG N-terminus; 2) removal of the IgG light chain or Fab regions; 3) addition of hexamer-inducing mutations in the IgG Fc; 4) adding a self-binding epitope tag to create recombinant immune complexes (RIC); or 5) producing IgG fusions in plants that lack plant-specific β1,2-linked xylose and α1,3-linked fucose N-linked glycans. We also characterized the expression, solubility, and stability of the IgG fusions. By optimizing the size of polymeric constructs, a potently immunogenic vaccine candidate with improved solubility and high stability was produced at 1.5 milligrams IgG fusion per gram leaf fresh weight (mg/g LFW). In mice, the various IgG fusions elicited high titers of Zika-specific antibodies using only two doses without adjuvant, up to 150-fold higher antibody titers than ZE3 alone. We anticipate these findings will be broadly applicable to the creation of vaccines and antibody-based therapeutics.HighlightsAntigen immunogenicity is improved up to 150-fold by fusion to plant-made IgGs.High serum IgG endpoint titers >1:500,000 were achieved with only two doses without adjuvant.A modified immune complex has high expression, solubility, stability, and immunogenicity.Competing Interest StatementThe authors have declared no competing interest.RICrecombinant immune complexZIKVZika virusZE3Zika virus envelope domain IIIFcthe C-terminal fragment of crystallization of IgGFcγFc from immunoglobulin GFabthe antigen-binding fragment of IgG6D8a human IgG1 monoclonal antibody targeting a linear epitope on Ebola virus glycoprotein 1C1qthe first component of the classical complement pathwayADCCantibody-dependent cellular cytotoxicityCDCcomplement dependent cytoctoxicityFcRnneonatal Fc receptors