Intranasal nanoemulsion adjuvanted S-2P vaccine demonstrates protection in hamsters and induces systemic, cell-mediated and mucosal immunity in mice

PLoS One. 2022 Nov 2;17(11):e0272594. doi: 10.1371/journal.pone.0272594. eCollection 2022.

Abstract

With the rapid progress made in the development of vaccines to fight the SARS-CoV-2 pandemic, almost >90% of vaccine candidates under development and a 100% of the licensed vaccines are delivered intramuscularly (IM). While these vaccines are highly efficacious against COVID-19 disease, their efficacy against SARS-CoV-2 infection of upper respiratory tract and transmission is at best temporary. Development of safe and efficacious vaccines that are able to induce robust mucosal and systemic immune responses are needed to control new variants. In this study, we have used our nanoemulsion adjuvant (NE01) to intranasally (IN) deliver stabilized spike protein (S-2P) to induce immunogenicity in mouse and hamster models. Data presented demonstrate the induction of robust immunity in mice resulting in 100% seroconversion and protection against SARS-CoV-2 in a hamster challenge model. There was a significant induction of mucosal immune responses as demonstrated by IgA- and IgG-producing memory B cells in the lungs of animals that received intranasal immunizations compared to an alum adjuvanted intramuscular vaccine. The efficacy of the S-2P/NE01 vaccine was also demonstrated in an intranasal hamster challenge model with SARS-CoV-2 and conferred significant protection against weight loss, lung pathology, and viral clearance from both upper and lower respiratory tract. Our findings demonstrate that intranasal NE01-adjuvanted vaccine promotes protective immunity against SARS-CoV-2 infection and disease through activation of three arms of immune system: humoral, cellular, and mucosal, suggesting that an intranasal SARS-CoV-2 vaccine may play a role in addressing a unique public health problem and unmet medical need.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic
  • Administration, Intranasal
  • Animals
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 Vaccines
  • COVID-19* / prevention & control
  • Cricetinae
  • Humans
  • Immunity, Mucosal*
  • Mice
  • SARS-CoV-2
  • Spike Glycoprotein, Coronavirus

Substances

  • COVID-19 Vaccines
  • Antibodies, Viral
  • Adjuvants, Immunologic
  • Antibodies, Neutralizing
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2

Grants and funding

C.C. and C.-E. L. are employees of Medigen Vaccine Biologics (Taipei, Taiwan) and they report receiving grants from Taiwan Centres for Disease Control, Ministry of Health and Welfare, during the conduct of the study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.