SARS-CoV-2 vaccination induces neutralizing antibodies against pandemic and pre-emergent SARS-related coronaviruses in monkeys.

Abstract

Betacoronaviruses (betaCoVs) caused the severe acute respiratory syndrome (SARS) and Middle East Respiratory Syndrome (MERS) outbreaks, and now the SARS-CoV-2 pandemic. Vaccines that elicit protective immune responses against SARS-CoV-2 and betaCoVs circulating in animals have the potential to prevent future betaCoV pandemics. Here, we show that immunization of macaques with a multimeric SARS-CoV-2 receptor binding domain (RBD) nanoparticle adjuvanted with 3M-052-Alum elicited cross-neutralizing antibody responses against SARS-CoV-1, SARS-CoV-2, batCoVs and the UK B.1.1.7 SARS-CoV-2 mutant virus. Nanoparticle vaccination resulted in a SARS-CoV-2 reciprocal geometric mean neutralization titer of 47,216, and robust protection against SARS-CoV-2 in macaque upper and lower respiratory tracts. Importantly, nucleoside-modified mRNA encoding a stabilized transmembrane spike or monomeric RBD protein also induced SARS-CoV-1 and batCoV cross-neutralizing antibodies, albeit at lower titers. These results demonstrate current mRNA vaccines may provide some protection from future zoonotic betaCoV outbreaks, and provide a platform for further development of pan-betaCoV nanoparticle vaccines.

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Published Version (Please cite this version)

10.1101/2021.02.17.431492

Publication Info

Saunders, Kevin O, Esther Lee, Robert Parks, David R Martinez, Dapeng Li, Haiyan Chen, Robert J Edwards, Sophie Gobeil, et al. (2021). SARS-CoV-2 vaccination induces neutralizing antibodies against pandemic and pre-emergent SARS-related coronaviruses in monkeys. bioRxiv. 10.1101/2021.02.17.431492 Retrieved from https://hdl.handle.net/10161/22410.

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Scholars@Duke

Saunders

Kevin O'Neil Saunders

Professor in Surgery

Dr. Kevin O. Saunders graduated from Davidson College in 2005 with a bachelor of science in biology. At Davidson College, he trained in the laboratory of Dr. Karen Hales identifying the genetic basis of infertility. Dr. Saunders completed his doctoral research on CD8+ T cell immunity against HIV-1 infection with Dr. Georgia Tomaras at Duke University in 2010. He subsequently trained as a postdoctoral fellow in the laboratories of Drs. Gary Nabel and John Mascola at the National Institutes of Health (NIH) National Institute of Allergy and Infectious Diseases (NIAID) Vaccine Research Center.

In 2014, Dr. Saunders joined the faculty at the Duke Human Vaccine Institute as a medical instructor. In this role, he analyzed antibody responses in vaccinated macaques, which led to the identification of glycan-dependent HIV antibodies induced by vaccination. Dr. Saunders was appointed as a non-tenure track Assistant Professor of Surgery and the Director of the Laboratory of Protein Expression in the Duke Human Vaccine Institute in 2015. He successfully transitioned to a tenure-track appointment in 2018 and was later promoted to the rank of Associate Professor in Surgery in 2020. Dr. Saunders previously served as DHVI's director or research and currently serves as the associate director for DHVI.

Dr. Saunders has given invited lectures at international conferences such as HIVR4P and the Keystone Symposia for HIV Vaccines. He has authored book chapters and numerous journal articles and holds patents on vaccine design concepts and antiviral antibodies. As a faculty member at Duke, Dr. Saunders has received the Duke Human Vaccine Institute Outstanding Leadership Award and the Norman Letvin Center For HIV/AIDS Vaccine Immunology and Immunogen Discovery Outstanding Investigator Award. His current research interests include vaccine and antibody development to combat HIV-1 and coronavirus infections.

About the Saunders Laboratory
The Saunders laboratory aims to understand the immunology of HIV-1 antibodies and the molecular biology of their interaction with HIV-1 envelope (Env) glycoprotein. Our overall goal is to develop protective antibody-based vaccines; therefore, the laboratory has two sections–antibody repertoire analysis and immunogen design. Our research premise is that vaccine-elicited antibodies will broadly neutralize HIV-1 if they can bind directly to the host glycans on Env. However, Env glycans are poorly immunogenic and require specific targeting by a vaccine immunogen to elicit an antibody response.

Anti-glycan HIV-1 antibody biology. The laboratory utilizes single B cell PCR to probe the antibody repertoire during natural infection and after vaccination. Using this technique we identified two monoclonal antibodies from HIV Env vaccinated macaques called DH501 and DH502 that bind directly to mannose glycans and to HIV-1 envelope (Env). We have characterized these antibodies using glycan immunoassays, antibody engineering, and x-ray crystallography to define the mechanisms of Env-glycan interaction by these antibodies. Glycan-reactive HIV antibodies are rarely elicited with HIV-1 vaccination; therefore we have studied the ontogeny of DH501 using longitudinal next generation sequencing and reversion of somatic mutations within the antibody variable regions. DH501 and DH502 antibodies are mostly found in the repertoire as IgG2 and IgM isotypes—similar to known natural glycan antibodies. Therefore we are examining whether vaccines mobilize antibodies from the natural glycan pool that affinity mature to interact with HIV-1 envelope. The results of these studies inform us about the similarities and differences between vaccine-induced glycan-reactive antibodies and known broadly neutralizing HIV-1 antibodies from human natural infection. These comparative studies define the molecular biology of glycan-reactive antibodies as well as determine how close current vaccines are to inducing glycan-dependent broadly neutralizing antibodies.

HIV-1 Env immunogen design. The discovery of lineages of broadly neutralizing antibodies in HIV-infected individuals has provided templates for vaccine design. With knowledge of the antibodies we desire to elicit we can engineer the HIV-1 Env to preferentially bind to those antibodies. We discovered that Man9GlcNAc2 is the glycan preferred by early precursors in broadly neutralizing antibody lineages. We translated this finding into a vaccine design strategy that we have termed “glycan learning.” This approach modifies the glycosylation of HIV-1 Env immunogens to be the optimal glycan type for engagement of the precursor antibody of glycan-reactive broadly neutralizing HIV-1 antibody lineages. The Env glycosylation sites and glycan type are then modified on subsequent Env immunogens to select antibodies that are maturing towards a broadly neutralizing phenotype. We have developed cell culture procedures and purification strategies combined with mass spectrometry analyses to create Env immunogens with specific glycosylation profiles. While the overall goal is to elicit protective neutralizing antibodies in vivo, we use these Env antigens in vitro to investigate the biology of B cell receptor engagement. More specifically, we investigate the effects of various immunogen delivery platforms, such as protein or gold nanoparticles, nucleic acid, or recombinant viral vectors on B cell activation.

Taken together, our research program is an interdisciplinary approach to understanding the molecular biology underlying antibody recognition of glycoproteins in order to produce protective vaccines.


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