Polymersomes as Stable Nanocarriers for a Highly Immunogenic and Durable SARS-CoV-2 Spike Protein Subunit Vaccine

Multiple successful vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are urgently needed to address the ongoing coronavirus disease 2019 (Covid-19) pandemic. In the present work, we describe a subunit vaccine based on the SARS-CoV-2 spike protein coadministered with CpG adjuvant. To enhance the immunogenicity of our formulation, both antigen and adjuvant were encapsulated with our proprietary artificial cell membrane (ACM) polymersome technology. Structurally, ACM polymersomes are self-assembling nanoscale vesicles made up of an amphiphilic block copolymer comprising poly(butadiene)-b-poly(ethylene glycol) and a cationic lipid, 1,2-dioleoyl-3-trimethylammonium-propane. Functionally, ACM polymersomes serve as delivery vehicles that are efficiently taken up by dendritic cells (DC1 and DC2), which are key initiators of the adaptive immune response. Two doses of our formulation elicit robust neutralizing antibody titers in C57BL/6 mice that persist at least 40 days. Furthermore, we confirm the presence of functional memory CD4+ and CD8+ T cells that produce T helper type 1 cytokines. This study is an important step toward the development of an efficacious vaccine in humans.

[1]  C. Wiysonge,et al.  COVID-19 vaccines , 2021, Current Opinion in Immunology.

[2]  A. Marchant,et al.  Immunological mechanisms of vaccine-induced protection against COVID-19 in humans , 2021, Nature Reviews Immunology.

[3]  M. Davenport,et al.  Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection , 2021, Nature Medicine.

[4]  Haiguang Liu,et al.  Harnessing peak transmission around symptom onset for non-pharmaceutical intervention and containment of the COVID-19 pandemic , 2021, Nature Communications.

[5]  Swapnil Mahajan,et al.  Immunodominant T-cell epitopes from the SARS-CoV-2 spike antigen reveal robust pre-existing T-cell immunity in unexposed individuals , 2020, Scientific Reports.

[6]  M. Nussenzweig,et al.  SARS-CoV-2 neutralizing antibody structures inform therapeutic strategies , 2020, Nature.

[7]  F. Ginhoux,et al.  Genetic models of human and mouse dendritic cell development and function , 2020, Nature reviews. Immunology.

[8]  H. Brüssow.  Faculty Opinions recommendation of SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls. , 2020, Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature.

[9]  Ralf Bartenschlager,et al.  Structures and distributions of SARS-CoV-2 spike proteins on intact virions , 2020, Nature.

[10]  R. Coffman,et al.  Development of CpG-adjuvanted stable prefusion SARS-CoV-2 spike antigen as a subunit vaccine against COVID-19 , 2020, Scientific Reports.

[11]  Martin Linster,et al.  SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls , 2020, Nature.

[12]  Chul-Joong Kim,et al.  Neutralizing Antibody Production in Asymptomatic and Mild COVID-19 Patients, in Comparison with Pneumonic COVID-19 Patients , 2020, Journal of clinical medicine.

[13]  Morten Nielsen,et al.  Robust T Cell Immunity in Convalescent Individuals with Asymptomatic or Mild COVID-19 , 2020, Cell.

[14]  Qiang Zhou,et al.  A neutralizing human antibody binds to the N-terminal domain of the Spike protein of SARS-CoV-2 , 2020, Science.

[15]  X. Tang,et al.  Clinical and immunological assessment of asymptomatic SARS-CoV-2 infections , 2020, Nature Medicine.

[16]  D. Burton,et al.  Isolation of potent SARS-CoV-2 neutralizing antibodies and protection from disease in a small animal model , 2020, Science.

[17]  Yuan Wang,et al.  Identifying airborne transmission as the dominant route for the spread of COVID-19 , 2020, Proceedings of the National Academy of Sciences.

[18]  J. Mascola,et al.  SARS-CoV-2 mRNA Vaccine Development Enabled by Prototype Pathogen Preparedness , 2020, bioRxiv.

[19]  C. Poh,et al.  Two linear epitopes on the SARS-CoV-2 spike protein that elicit neutralising antibodies in COVID-19 patients , 2020, Nature Communications.

[20]  Marc C. Johnson,et al.  Optimized Pseudotyping Conditions for the SARS-COV-2 Spike Glycoprotein , 2020, Journal of Virology.

[21]  J. Greenbaum,et al.  Targets of T Cell Responses to SARS-CoV-2 Coronavirus in Humans with COVID-19 Disease and Unexposed Individuals , 2020, Cell.

[22]  H. Achdout,et al.  Tiger team: a panel of human neutralizing mAbs targeting SARS-CoV-2 spike at multiple epitopes , 2020, bioRxiv.

[23]  M. V. van Breemen,et al.  Potent neutralizing antibodies from COVID-19 patients define multiple targets of vulnerability , 2020, Science.

[24]  H. Yen,et al.  Peer Review File Manuscript Title: Pathogenesis and transmission of SARS-CoV-2 in golden Syrian hamsters , 2020 .

[25]  J. Leroux,et al.  Twenty-five years of polymersomes: lost in translation? , 2020, Materials Horizons.

[26]  Barney S. Graham,et al.  Rapid COVID-19 vaccine development , 2020, Science.

[27]  Yusen Duan,et al.  Aerodynamic analysis of SARS-CoV-2 in two Wuhan hospitals , 2020, Nature.

[28]  M. Koopmans,et al.  SARS-CoV-2 is transmitted via contact and via the air between ferrets , 2020, bioRxiv.

[29]  C. Hillyer,et al.  Neutralizing Antibodies against SARS-CoV-2 and Other Human Coronaviruses , 2020, Trends in Immunology.

[30]  B. Liedberg,et al.  Facile Mixing of Phospholipids Promotes Self-Assembly of Low-Molecular-Weight Biodegradable Block Co-Polymers into Functional Vesicular Architectures , 2020, Polymers.

[31]  Yan Liu,et al.  Characterization of spike glycoprotein of SARS-CoV-2 on virus entry and its immune cross-reactivity with SARS-CoV , 2020, Nature Communications.

[32]  A. Walls,et al.  Structure, Function, and Antigenicity of the SARS-CoV-2 Spike Glycoprotein , 2020, Cell.

[33]  G. Herrler,et al.  SARS-CoV-2 Cell Entry Depends on ACE2 and TMPRSS2 and Is Blocked by a Clinically Proven Protease Inhibitor , 2020, Cell.

[34]  A. M. Leontovich,et al.  The species Severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2 , 2020, Nature Microbiology.

[35]  Zunyou Wu,et al.  Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention. , 2020, JAMA.

[36]  M. Blenner,et al.  Polymersomes for therapeutic delivery of protein and nucleic acid macromolecules: From design to therapeutic applications. , 2020, Biomacromolecules.

[37]  Yuanyu Huang,et al.  The challenge and prospect of mRNA therapeutics landscape. , 2020, Biotechnology advances.

[38]  J. Nie,et al.  Establishment and validation of a pseudovirus neutralization assay for SARS-CoV-2 , 2020, Emerging microbes & infections.

[39]  Petra Schwille,et al.  Liposomes and polymersomes: a comparative review towards cell mimicking. , 2018, Chemical Society reviews.

[40]  X. Tao,et al.  A CpG oligodeoxynucleotide enhances the immune response to rabies vaccination in mice , 2018, Virology Journal.

[41]  Jianbo Jia,et al.  Interactions Between Nanoparticles and Dendritic Cells: From the Perspective of Cancer Immunotherapy , 2018, Front. Oncol..

[42]  Yanbo Ma,et al.  Nanotoxicity of Silver Nanoparticles on HEK293T Cells: A Combined Study Using Biomechanical and Biological Techniques , 2018, ACS omega.

[43]  F. Ginhoux,et al.  Homeostatic control of dendritic cell numbers and differentiation , 2018, Immunology and cell biology.

[44]  Han‐Gon Choi,et al.  Optimization and physicochemical characterization of a cationic lipid-phosphatidylcholine mixed emulsion formulated as a highly efficient vehicle that facilitates adenoviral gene transfer , 2017, International journal of nanomedicine.

[45]  M. Bachmann,et al.  Delivering adjuvants and antigens in separate nanoparticles eliminates the need of physical linkage for effective vaccination , 2017, Journal of controlled release : official journal of the Controlled Release Society.

[46]  C. Weyand,et al.  The life cycle of a T cell after vaccination – where does immune ageing strike? , 2017, Clinical and experimental immunology.

[47]  D. Meyerholz,et al.  RSV Vaccine-Enhanced Disease Is Orchestrated by the Combined Actions of Distinct CD4 T Cell Subsets , 2015, PLoS pathogens.

[48]  T. Lawrence,et al.  Dendritic cell maturation: functional specialization through signaling specificity and transcriptional programming , 2014, The EMBO journal.

[49]  J. Hubbell,et al.  Tunable T cell immunity towards a protein antigen using polymersomes vs. solid-core nanoparticles. , 2013, Biomaterials.

[50]  D. W. Pack,et al.  Design of hybrid lipid/retroviral-like particle gene delivery vectors. , 2013, Molecular pharmaceutics.

[51]  K. Steinbrink,et al.  Costimulatory Molecules on Immunogenic Versus Tolerogenic Human Dendritic Cells , 2013, Front. Immunol..

[52]  Miriam Merad,et al.  The dendritic cell lineage: ontogeny and function of dendritic cells and their subsets in the steady state and the inflamed setting. , 2013, Annual review of immunology.

[53]  J. Hubbell,et al.  Dendritic cell activation and T cell priming with adjuvant- and antigen-loaded oxidation-sensitive polymersomes. , 2012, Biomaterials.

[54]  S. Mittal,et al.  Adenoviral vector immunity: its implications and circumvention strategies. , 2011, Current gene therapy.

[55]  Wah Chiu,et al.  Interbilayer-Crosslinked Multilamellar Vesicles as Synthetic Vaccines for Potent Humoral and Cellular Immune Responses , 2011, Nature materials.

[56]  E. Clark,et al.  The role of CD40 and CD154/CD40L in dendritic cells. , 2009, Seminars in immunology.

[57]  A. Halperin.  Polymeric vs. Monomeric Amphiphiles: Design Parameters , 2006 .

[58]  W. Hong,et al.  Monoclonal Antibodies Targeting the HR2 Domain and the Region Immediately Upstream of the HR2 of the S Protein Neutralize In Vitro Infection of Severe Acute Respiratory Syndrome Coronavirus , 2006, Journal of Virology.

[59]  A. Iwasaki,et al.  Toll-like receptor control of the adaptive immune responses , 2004, Nature Immunology.

[60]  Praveen Elamanchili,et al.  Dose sparing of CpG oligodeoxynucleotide vaccine adjuvants by nanoparticle delivery. , 2004, Current drug delivery.

[61]  H. Davis,et al.  CpG ODN can re-direct the Th bias of established Th2 immune responses in adult and young mice. , 2001, FEMS immunology and medical microbiology.

[62]  R. Kammerer,et al.  Stabilization of short collagen-like triple helices by protein engineering. , 2001, Journal of molecular biology.

[63]  D. Hammer,et al.  Polymersomes: tough vesicles made from diblock copolymers. , 1999, Science.

[64]  H. Six,et al.  Immunoglobulin G subclass antibody responses of mice to influenza virus antigens given in different forms. , 1987, Antiviral research.

[65]  J. Snick,et al.  IgG2a restriction of murine antibodies elicited by viral infections , 1987, The Journal of experimental medicine.

[66]  R. Chanock,et al.  Respiratory syncytial virus disease in infants despite prior administration of antigenic inactivated vaccine. , 1969, American journal of epidemiology.

[67]  J. Luban.  SARS-CoV-2 , 2020 .

[68]  J. Pallesen,et al.  Prefusion coronavirus spike proteins and their use , 2017 .

[69]  V. Fulginiti,et al.  Altered reactivity to measles virus. Atypical measles in children previously immunized with inactivated measles virus vaccines. , 1967, JAMA.