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Schwedler JL, Stefan MA, Thatcher CE, McIlroy PR, Sinha A, Phillips AM, Sumner CA, Courtney CM, Kim CY, Weilhammer DR, Harmon B. Therapeutic efficacy of a potent anti-Venezuelan equine encephalitis virus antibody is contingent on Fc effector function. MAbs 2024; 16:2297451. [PMID: 38170638 PMCID: PMC10766394 DOI: 10.1080/19420862.2023.2297451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024] Open
Abstract
The development of specific, safe, and potent monoclonal antibodies (Abs) has led to novel therapeutic options for infectious disease. In addition to preventing viral infection through neutralization, Abs can clear infected cells and induce immunomodulatory functions through engagement of their crystallizable fragment (Fc) with complement proteins and Fc receptors on immune cells. Little is known about the role of Fc effector functions of neutralizing Abs in the context of encephalitic alphavirus infection. To determine the role of Fc effector function in therapeutic efficacy against Venezuelan equine encephalitis virus (VEEV), we compared the potently neutralizing anti-VEEV human IgG F5 (hF5) Ab with intact Fc function (hF5-WT) or containing the loss of function Fc mutations L234A and L235A (hF5-LALA) in the context of VEEV infection. We observed significantly reduced binding to complement and Fc receptors, as well as differential in vitro kinetics of Fc-mediated cytotoxicity for hF5-LALA compared to hF5-WT. The in vivo efficacy of hF5-LALA was comparable to hF5-WT at -24 and + 24 h post infection, with both Abs providing high levels of protection. However, when hF5-WT and hF5-LALA were administered + 48 h post infection, there was a significant decrease in the therapeutic efficacy of hF5-LALA. Together these results demonstrate that optimal therapeutic Ab treatment of VEEV, and possibly other encephalitic alphaviruses, requires neutralization paired with engagement of immune effectors via the Fc region.
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Affiliation(s)
- Jennifer L. Schwedler
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Maxwell A. Stefan
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Christine E. Thatcher
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Peter R. McIlroy
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Anupama Sinha
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Ashlee M. Phillips
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Christopher A. Sumner
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Colleen M. Courtney
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Christina Y. Kim
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
| | - Dina R. Weilhammer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Brooke Harmon
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, CA, USA
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Stefan MA, Light YK, Schwedler JL, McIlroy PR, Courtney CM, Saada EA, Thatcher CE, Phillips AM, Bourguet FA, Mageeney CM, McCloy SA, Collette NM, Negrete OA, Schoeniger JS, Weilhammer DR, Harmon B. Development of potent and effective synthetic SARS-CoV-2 neutralizing nanobodies. MAbs 2021; 13:1958663. [PMID: 34348076 PMCID: PMC8344751 DOI: 10.1080/19420862.2021.1958663] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/07/2021] [Accepted: 07/19/2021] [Indexed: 02/06/2023] Open
Abstract
The respiratory virus responsible for coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected nearly every aspect of life worldwide, claiming the lives of over 3.9 million people globally, at the time of this publication. Neutralizing humanized nanobody (VHH)-based antibodies (VHH-huFc) represent a promising therapeutic intervention strategy to address the current SARS-CoV-2 pandemic and provide a powerful toolkit to address future virus outbreaks. Using a synthetic, high-diversity VHH bacteriophage library, several potent neutralizing VHH-huFc antibodies were identified and evaluated for their capacity to tightly bind to the SARS-CoV-2 receptor-binding domain, to prevent binding of SARS-CoV-2 spike (S) to the cellular receptor angiotensin-converting enzyme 2, and to neutralize viral infection. Preliminary preclinical evaluation of multiple VHH-huFc antibody candidates demonstrate that they are prophylactically and therapeutically effective in vivo against wildtype SARS-CoV-2. The identified and characterized VHH-huFc antibodies described herein represent viable candidates for further preclinical evaluation and another tool to add to our therapeutic arsenal to address the COVID-19 pandemic.
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Affiliation(s)
- Maxwell A. Stefan
- Systems Biology Department, Sandia National Laboratories, Livermore, USA
| | - Yooli K. Light
- Systems Biology Department, Sandia National Laboratories, Livermore, USA
| | - Jennifer L. Schwedler
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, USA
| | - Peter R. McIlroy
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, USA
| | - Colleen M. Courtney
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, USA
| | - Edwin A. Saada
- Systems Biology Department, Sandia National Laboratories, Livermore, USA
| | - Christine E. Thatcher
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, USA
| | - Ashlee M. Phillips
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratories, Livermore, USA
| | - Feliza A. Bourguet
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratories, Livermore, USA
| | | | - Summer A. McCloy
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratories, Livermore, USA
| | - Nicole M. Collette
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratories, Livermore, USA
| | - Oscar A. Negrete
- Biotechnology and Bioengineering Department, Sandia National Laboratories, Livermore, USA
| | | | - Dina R. Weilhammer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratories, Livermore, USA
| | - Brooke Harmon
- Systems Biology Department, Sandia National Laboratories, Livermore, USA
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