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Liu X, Drelich A, Li W, Chen C, Sun Z, Shi M, Adams C, Mellors JW, Tseng CT, Dimitrov DS. Enhanced elicitation of potent neutralizing antibodies by the SARS-CoV-2 spike receptor binding domain Fc fusion protein in mice. Vaccine 2020; 38:7205-7212. [PMID: 33010978 PMCID: PMC7508516 DOI: 10.1016/j.vaccine.2020.09.058] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/19/2020] [Accepted: 09/20/2020] [Indexed: 01/23/2023]
Abstract
SARS-CoV-2 RBD-Fc elicited higher neutralizing antibodies titer than RBD. Cell–cell fusion assay showed a strong correlation with the neutralization assay. Anti-RBD sera did not enhance the pseudotyped SARS-CoV-2 infection of K562 cells.
The development of an effective vaccine against SARS-CoV-2 is urgently needed. We generated SARS-CoV-2 RBD-Fc fusion protein and evaluated its potency to elicit neutralizing antibody response in mice. RBD-Fc elicited a higher neutralizing antibodies titer than RBD as evaluated by a pseudovirus neutralization assay and a live virus based microneutralization assay. Furthermore, RBD-Fc immunized sera better inhibited cell–cell fusion, as evaluated by a quantitative cell–cell fusion assay. The cell–cell fusion assay results correlated well with the virus neutralization potency and could be used for high-throughput screening of large panels of anti-SARS-CoV-2 antibodies and vaccines without the requirement of live virus infection in BSL3 containment. Moreover, the anti-RBD sera did not enhance the pseudotyped SARS-CoV-2 infection of K562 cells. These results demonstrate that Fc fusion can significantly improve the humoral immune response to recombinant RBD immunogen, and suggest that RBD-Fc could serve as a useful component of effective vaccines against SARS-CoV-2.
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Affiliation(s)
- Xianglei Liu
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA.
| | - Aleksandra Drelich
- Department of Microbiology & Immunology, Centers for Biodefense and Emerging Diseases, Galveston National Laboratory, 301 University Blvd, Galveston, TX 77550, USA
| | - Wei Li
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA
| | - Chuan Chen
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA
| | - Zehua Sun
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA
| | - Megan Shi
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA
| | - Cynthia Adams
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA
| | - John W Mellors
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA; Abound Bio, 1401 Forbes Ave, Pittsburgh, PA 15219, USA
| | - Chien-Te Tseng
- Department of Microbiology & Immunology, Centers for Biodefense and Emerging Diseases, Galveston National Laboratory, 301 University Blvd, Galveston, TX 77550, USA
| | - Dimiter S Dimitrov
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical School, 3550 Terrace St, Pittsburgh, PA 15261, USA; Abound Bio, 1401 Forbes Ave, Pittsburgh, PA 15219, USA.
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