Safe, effective, and economical vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to achieve adequate herd immunity and end the pandemic. We constructed a novel SARS-CoV-2 vaccine, CoVac501, which is a self-adjuvanting peptide vaccine conjugated with Toll-like receptor 7 (TLR7) agonists. The vaccine contains immunodominant peptides screened from the receptor-binding domain (RBD) and is fully chemically synthesized. It has been formulated in an optimized nanoemulsion formulation and is stable at 40 °C for 1 month. In non-human primates (NHPs), CoVac501 elicited high and persistent titers of protective neutralizing antibodies against multiple RBD mutations, SARS-CoV-2 original strain, and variants (B.1.1.7 and B.1.617.2). Specific peptides booster immunization against the B.1.351 variant has also been shown to be effective in improving protection against B.1.351. Meanwhile, CoVac501 elicited the increase of memory T cells, antigen-specific CD8 + T-cell responses, and Th1-biased CD4 + T-cell immune responses in NHPs. Notably, at an extremely high SARS-CoV-2 challenge dose of 1 × 10 7 TCID 50 , CoVac501 provided near-complete protection for the upper and lower respiratory tracts of cynomolgus macaques.
【저자키워드】 immunology, Biological techniques, 【초록키워드】 SARS-CoV-2, Vaccine, coronavirus, pandemic, Immunity, B.1.351, variant, TLR7, B.1.617.2, peptide, CD4, CD8, immunization, SARS-CoV-2 vaccine, B.1.1.7, RBD, NHPs, memory T cells, non-human primate, booster, T-cell responses, cynomolgus macaques, T-cell immune response, RBD mutations, dose, Lower respiratory tract, acute respiratory syndrome, B.1.351 variant, Specific, toll-like receptor 7, TCID, immunodominant, effective, agonists, shown, provided, screened, the receptor-binding domain, elicited, protective neutralizing antibody, 【제목키워드】 SARS-CoV-2, Vaccine, TLR7, peptide, protective immunity, agonists, induce,