RT Journal Article
SR Electronic
T1 Sialic acid and fucose residues on the SARS-CoV-2 receptor binding domain modulate IgG reactivity
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.01.20.477056
DO 10.1101/2022.01.20.477056
A1 Samuelsson, Ebba
A1 Mirgorodskaya, Ekaterina
A1 Nyström, Kristina
A1 Bäckström, Malin
A1 Liljeqvist, Jan-Åke
A1 Nordén, Rickard
YR 2022
UL http://biorxiv.org/content/early/2022/01/21/2022.01.20.477056.abstract
AB The receptor binding domain (RBD) of the SARS-CoV-2 spike protein is a conserved domain and a target for neutralizing antibodies. We defined the carbohydrate content of recombinant RBD produced in different mammalian cells. We found a higher degree of complex type N-linked glycans, with less sialylation and more fucosylation, when the RBD was produced in Human embryonic kidney cells compared to the same protein produced in Chinese hamster ovary cells. The carbohydrates on the RBD proteins were enzymatically modulated and the effect on antibody reactivity was evaluated with serum samples from SARS-CoV-2 positive patients. Removal of all carbohydrates diminished antibody reactivity while removal of only sialic acids or terminal fucoses improved the reactivity. The RBD produced in Lec3.2.8.1-cells, which generate carbohydrate structures devoid of sialic acids and with reduced fucose content, exhibited enhanced antibody reactivity verifying the importance of these specific monosaccharides. The results can be of importance for the design of future vaccine candidates, indicating that it might be possible to enhance the immunogenicity of recombinant viral proteins.