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- Title
A novel monospecific tetravalent IgG1-(scFv)<sub>2</sub> version shown enhanced neutralizing and Fc-mediated effector functions against SARS-CoV-2.
- Authors
Gao, Zhang-zhao; Jiao, Jing-yu; Zhou, Ya-qiong; Qi, Jian; Zhu, Shan-shan; Xu, Jing-ya; Nie, Lei; Wang, Hai-bin
- Abstract
Neutralizing monoclonal antibodies (nMABs) have been proved to be effective therapeutics in treating coronavirus disease (COVID-19). To enhance the potency of nMAB 553–15, we generated a novel monospecific tetravalent IgG1-(scFv)2 version. This was achieved by covalently fusing two forms of 553–15-derived single chain variable fragments (scFv) to the C-terminus of the hIgG1 (human Immunoglobulin G1) Fc fragment. We found that the Fc-fused VL-linker-VH format achieved similar binding affinity and neutralizing behavior as 553–15. The tetravalent versions were constructed by fusing the scFv domains to the C-terminus of nMAB 553–15. As a result, the tetravalent version 55,315-VLVH exhibited significantly higher binding activity to target spike protein variants and enhanced neutralization against VOCs (variants of concern) pseudovirus compared to 553–15. We also measured the Fc effector responses of candidates using wild-type Spike-expressing CHOK1 cells. The 55,315-VLVH enhanced the function of ADCP (antibody-dependent cellular phagocytosis) but had similar IL-6 release levels compared to the bivalent 553–15. It seemed that the novel tetravalent version avoids the pro-inflammatory effect induced by macrophage activation. However, the 55,315-VLVH displayed slightly increased potency in ADCC (antibody-dependent cell-mediated cytotoxicity) and CDC (complement-dependent cytotoxicity), which might contribute to higher systemic inflammation. Further investigation is necessary to determine whether the tetravalent version is beneficial to balance efficiency and safety against COVID-19.
- Subjects
CENTERS for Disease Control &; Prevention (U.S.); IMMUNE response; ANTIBODY-dependent cell cytotoxicity; MONOCLONAL antibodies; SARS-CoV-2; COVID-19; MACROPHAGE activation; FC receptors
- Publication
3 Biotech, 2023, Vol 13, Issue 8, p1
- ISSN
2190-572X
- Publication type
Article
- DOI
10.1007/s13205-023-03702-z