Abstract
We report a live-attenuated SARS-CoV-2 vaccine candidate with (i) re-engineered viral transcription regulator sequences and (ii) deleted open-reading-frames (ORF) 3, 6, 7, and 8 (∆3678). The ∆3678 virus replicates about 7,500-fold lower than wild-type SARS-CoV-2 on primary human airway cultures, but restores its replication on interferon-deficient Vero-E6 cells that are approved for vaccine production. The ∆3678 virus is highly attenuated in both hamster and K18-hACE2 mouse models. A single-dose immunization of the ∆3678 virus protects hamsters from wild-type virus challenge and transmission. Among the deleted ORFs in the ∆3678 virus, ORF3a accounts for the most attenuation through antagonizing STAT1 phosphorylation during type-I interferon signaling. We also developed an mNeonGreen reporter ∆3678 virus for high-throughput neutralization and antiviral testing. Altogether, the results suggest that ∆3678 SARS-CoV-2 may serve as a live-attenuated vaccine candidate and a research tool for potential biosafety level-2 use.
【초록키워드】 SARS-CoV-2, Antiviral, hamsters, neutralization, live-attenuated vaccine, interferon, Transmission, virus, immunization, SARS-CoV-2 vaccine, biosafety, Replication, Viral, ORF3a, Research, Phosphorylation, interferon signaling, hamster, Stat1, Mouse models, reporter, ORFs, K18-hACE2, sequence, wild-type SARS-CoV-2, wild-type virus, cultures, vaccine production, viral transcription, primary human airway, mNeonGreen, PROTECT, approved, replicate, ORF, deleted, Vero-E6 cell, 【제목키워드】 SARS-CoV-2 vaccine, Protein, Deletion,