ESCRT recruitment to SARS-CoV-2 spike induces virus-like particles that improve mRNA vaccines

Creators: Hoffmann, Magnus A. G.; Yang, Zhi; Huey-Tubman, Kathryn E.; Cohen, Alexander A.; Gnanapragasam, Priyanthi N. P.; Nakatomi, Leesa M.; Storm, Kaya N.; Moon, Woohyun J.; Lin, Paulo J. C.; West, Anthony P., Jr.; Bjorkman, Pamela J.

Abstract

Prime-boost regimens for COVID-19 vaccines elicit poor antibody responses against Omicron-based variants and employ frequent boosters to maintain antibody levels. We present a natural infection-mimicking technology that combines features of mRNA- and protein nanoparticle-based vaccines through encoding self-assembling enveloped virus-like particles (eVLPs). eVLP assembly is achieved by inserting an ESCRT- and ALIX-binding region (EABR) into the SARS-CoV-2 spike cytoplasmic tail, which recruits ESCRT proteins to induce eVLP budding from cells. Purified spike-EABR eVLPs presented densely arrayed spikes and elicited potent antibody responses in mice. Two immunizations with mRNA-LNP encoding spike-EABR elicited potent CD8+ T cell responses and superior neutralizing antibody responses against original and variant SARS-CoV-2 compared with conventional spike-encoding mRNA-LNP and purified spike-EABR eVLPs, improving neutralizing titers >10-fold against Omicron-based variants for 3 months post-boost. Thus, EABR technology enhances potency and breadth of vaccine-induced responses through antigen presentation on cell surfaces and eVLPs, enabling longer-lasting protection against SARS-CoV-2 and other viruses.

Additional Information

© 2023 The Author(s). Published by Elsevier Under a Creative Commons license Attribution 4.0 International (CC BY 4.0) We thank J. Vielmetter and the Caltech Protein Expression Center for assistance with protein production; K. Dam for biotinylated proteins for ELISAs; M. Anaya for a BirA expression plasmid; and J. Bloom (Fred Hutchinson) and P. Bieniasz (Rockefeller University) for neutralization assay reagents. We thank J. Keeffe, Y. Tam (Acuitas Therapeutics), C. Barnes (Stanford), H. Kleanthous (Bill and Melinda Gates Foundation), B. Wold, G. Tolomiczenko, and the Caltech Merkin Institute for Translational Research for helpful discussions. Electron tomography was performed in the Caltech Cryo-EM Center with assistance from S. Chen. We thank Labcorp Drug Development-Antibody Reagents and Vaccines (Denver, PA) (formerly Covance, Inc.) for mouse immunization studies, BIOQUAL, Inc. (Rockville, MD) for PRNT50 assays, and R. Sukhovershin and RNAcore (Houston Methodist Research Institute) for synthesis of mRNAs and helpful discussion. Figures 1A and 3A were created with Biorender.com. This work was supported by the Bill and Melinda Gates Foundation INV-034638 (P.J.B.), the Caltech Merkin Institute (P.J.B.), the George Mason University Fast Grants (P.J.B.), the Rothenberg Innovation Initiative (RI2) (P.J.B.), and Wellcome Leap (P.J.B.). M.A.G.H. was supported by an NIH Director's Early Independence Award (FAIN# DP5OD033362). Author contributions. M.A.G.H. and P.J.B. conceived the study, acquired funding, analyzed the data, and wrote the manuscript with contributions from other authors (Z.Y., P.J.C.L., and A.P.W.). M.A.G.H. and K.E.H.-T. generated, expressed, and evaluated EABR constructs by western blot and flow cytometry analysis. M.A.G.H., K.E.H.-T., P.N.P.G., L.M.N., and K.N.S. evaluated serum antibody responses from immunized mice by ELISA and neutralization assays. Z.Y. performed cryo-ET and interpreted results. A.A.C. prepared S-mi3 immunogens for immunization studies in mice. W.J.M. and P.J.C.L. prepared mRNA-LNP for immunization studies in mice. Inclusion and diversity. We support inclusive, diverse, and equitable conduct of research. Data and code availability. All data are available in the main text or the supplemental information. Materials are available upon request to the corresponding authors with a signed material transfer agreement. Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon request. This paper does not report original code. This work is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/. This license does not apply to figures/photos/artwork or other content included in the article that is credited to a third party; obtain authorization from the rights holder before using such material. Declaration of interests. M.A.G.H. and P.J.B. are inventors on a US patent application filed by the California Institute of Technology that covers the EABR technology described in this work. W.J.M. and P.J.C.L. are employees of Acuitas Therapeutics, a company developing LNP delivery technology; P.J.C.L. holds equity in Acuitas Therapeutics.

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