RT Journal Article
SR Electronic
T1 SARS-CoV-2 RBD219-N1C1: A Yeast-Expressed SARS-CoV-2 Recombinant Receptor-Binding Domain Candidate Vaccine Stimulates Virus Neutralizing Antibodies and T-cell Immunity in Mice
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.11.04.367359
DO 10.1101/2020.11.04.367359
A1 Jeroen Pollet
A1 Wen-Hsiang Chen
A1 Leroy Versteeg
A1 Brian Keegan
A1 Bin Zhan
A1 Junfei Wei
A1 Zhuyun Liu
A1 Jungsoon Lee
A1 Rahki Kundu
A1 Rakesh Adhikari
A1 Cristina Poveda
A1 Maria-Jose Villar Mondragon
A1 Ana Carolina de Araujo Leao
A1 Joanne Altieri Rivera
A1 Portia M. Gillespie
A1 Ulrich Strych
A1 Peter J. Hotez
A1 Maria Elena Bottazzi
YR 2020
UL http://biorxiv.org/content/early/2020/11/05/2020.11.04.367359.abstract
AB There is an urgent need for an accessible and low-cost COVID-19 vaccine suitable for low- and middle-income countries. Here we report on the development of a SARS-CoV-2 receptor-binding domain (RBD) protein, expressed at high levels in yeast (Pichia pastoris), as a suitable vaccine candidate against COVID-19. After introducing two modifications into the wild-type RBD gene to reduce yeast-derived hyperglycosylation and improve stability during protein expression, we show that the recombinant protein, RBD219-N1C1, is equivalent to the wild-type RBD recombinant protein (RBD219-WT) in an in vitro ACE-2 binding assay. Immunogenicity studies of RBD219-N1C1 and RBD219-WT proteins formulated with Alhydrogel® were conducted in mice, and, after two doses, both the RBD219-WT and RBD219-N1C1 vaccines induced high levels of binding IgG antibodies. Using a SARS-CoV-2 pseudovirus, we further showed that sera obtained after a two-dose immunization schedule of the vaccines were sufficient to elicit strong neutralizing antibody titers in the 1:1,000 to 1:10,000 range, for both antigens tested. The vaccines induced IFN-γ, IL-6, and IL-10 secretion, among other cytokines. Overall, these data suggest that the RBD219-N1C1 recombinant protein, produced in yeast, is suitable for further evaluation as a human COVID-19 vaccine, in particular, in an Alhydrogel® containing formulation and possibly in combination with other immunostimulants.Competing Interest StatementThe authors declare that Baylor College of Medicine recently licensed the RBD219-N1C1 technology to an Indian manufacturer for further development. The research conducted in this paper was performed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.