Comparative analysis of spike-specific IgG Fc glycoprofiles elicited by adenoviral, mRNA, and protein-based SARS-CoV-2 vaccines

Non-neutralizing functions in anti-SARS-CoV-2 IgG antibodies

“… Function Assay type Description Fcγ-affinity ELISA Bind antibodies to immobilized antigens and add to the biotinylated Fc receptor. With enzyme-linked streptavidin, the binding can be assayed [ 82 ] Flow cytometry Beads or cells with the specific Fc receptor or antigen are incubated with serum or antibodies and then identified by co-immunostaining [ 87 ] Complement Bead based Fluorescent beads with the antigen are incubated with antibodies. Complement is added.…”

“…The fluorescence is measured as ADCC activity [ 26 ] Target cell based Target cells expressing the antigen are incubated with antibodies. Effector cells are co-incubated, and cell death is measured as an indicator for ADCC activation [ 26 , 40 ] ELISA FcγRIIIa affinity is used as a proxy for NK-cell activity [ 82 ] Antibody mediated inflammation Cell based Either immobilized antigen or pseudovirus with antigen are incubated with antibodies and, when coincubated with effector cells, The cytokine release is then measured by ELISA in the supernatant [ 27 , 45 ]. …”

“…If an individual was already recovered before vaccination or received an adenovector vaccination, no afucosylation occurred [ 77 , 78 ]⁠, indicating that afucosylation appears only in immune-naive individuals shortly after seroconversion. In adenovector and protein subunit vaccines, no afucosylation occurred after the first dose [ 77 , 81 , 82 ]⁠. While adenovector and inactivated vaccines themselves may not be sufficient for an effective immune response, they could still be useful in preventing IgG afucosylation as a first dose before the application of mRNA vaccines if afucosylation is not desired.…”

Specific long-term changes in anti-SARS-CoV-2 IgG modifications and antibody functions in mRNA, adenovector, and protein subunit vaccines

“…The scoring system was based on the GlyxtoolMS software (12). Fucosylation, galactosylation, and sialylation were estimated by normalizing the sum of the signals of all IgG1 N-297 glycopeptides, as done in previous studies 13,14 .…”

Interaction of Asn297-Linked Glycan Ligands with the Fc Fragment of the Immunoglobulin Class G1: A Molecular Dynamics Simulation Study

“…The immunoglobulin class G (IgG) is composed of two antigen-binding fragments (Fabs) and one crystallizable fragment (Fc), which has the ability to recognize and eliminate pathogens. − The IgG can essentially bind with high specificity to any antigen due to the diversity of the antigen recognition Fab domains. The Fc proteins can be engineered into multimeric structures (hexa-Fcs) that bind their cognate receptors, which is an attractive scaffold for designing of novel therapeutics. , Particularly, the glycosylation positioned at Asn297 of the Fc region of IgG is centrally important to initiate a robust ADCC (antibody dependent cell-mediated cytotoxicity) response and interact with a variety of receptors, which are determined by the amino acid and glycan composition of the Fc. − For example, the composition of the Fc protein and the Asn297-linked glycans could alter the effector functions of IgG by modulating its affinity for Fcγ receptors. − It has been reported that the glycosylation at Asn297 is critical for interactions with Fc receptors and complement and that glycosylation at Asn563 is essential for controlling multimerization. , Compared to the glycosylated Fc structure, the aglycosylated Fc displays a larger Gyration Radii (Rg) and a more open CH2 orientation, which provides a better understanding of the physiologically relevant conformation of the Fc domain in solution. In addition, the glycosylation has also been considered as one of the important critical quality attributes of therapeutic monoclonal antibodies in biologic manufacturing. − Therefore, a detailed understanding of the mechanisms that the Fc protein responds to glycans in maintaining the quaternary structure and stability of Fc could illuminate their contributions to immunological functioning and facilitate the design of new Fc-targeted therapeutics.…”