The development of COVID-19 vaccines is critical in controlling global health issues under the COVID-19 pandemic. The subunit vaccines are the safest and most widely used vaccine platform and highly effective against a multitude of infectious diseases. An adjuvant is essential for subunit vaccines to enhance the magnitude and durability of immune responses. In this study, we determined whether a combination of toll-like receptor (TLR)1/2 and TLR3 agonists ( L -pampo) can be a potent adjuvant for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) subunit vaccine. We measured a neutralizing antibody (nAb) and an angiotensin-converting enzyme 2 (ACE2) receptor-blocking antibody against SARS-CoV-2 receptor-binding domain (RBD). We also detected interferon-gamma (IFN-γ) production by using ELISPOT and ELISA assays. By employing a ferret model, we detected nAbs and IFN-γ producing cells and measured viral load in nasal wash after the challenge of SARS-CoV-2. We found that SARS-CoV-2 antigens with L-pampo stimulated robust humoral and cellular immune responses. The efficacy of L-pampo was higher than the other adjuvants. Furthermore, in the ferret model, SARS-CoV-2 antigens with L-pampo elicited nAb response and antigen-specific cellular immune response against SARS-CoV-2, resulting in substantially decreased viral load in their nasal wash. Our study suggests that SARS-CoV-2 antigens formulated with TLR agonists, L-pampo, can be a potent subunit vaccine to promote sufficient protective immunity against SARS-CoV-2.
【저자키워드】 neutralizing antibody, SARS-CoV-2, TLR agonist, mucosal immunity, Subunit vaccine, adjuvant, Cell-mediated immunity, ferret model, IFN-γ-producing T cell, 【초록키워드】 Efficacy, ACE2, Vaccine, coronavirus, COVID-19 vaccine, Diseases, antibody, Cellular immune response, COVID-19 pandemic, nasal, adjuvants, angiotensin-converting enzyme 2, Toll-like receptor, Health, Viral load, protective immunity, RBD, immune responses, vaccine platform, SARS-CoV-2 antigen, Critical, IFN-γ, NAb, TLR3, Combination, humoral, acute respiratory syndrome, subunit, domain, cellular immune responses, agonist, TLR agonists, ELISA assays, effective, Cell, robust, ENhance, stimulated, resulting, promote, magnitude, producing, elicited, 【제목키워드】 COVID-19, TLR3, agonist,