Journal Article

Prime-boost vaccination of mice and rhesus macaques with two novel adenovirus vectored COVID-19 vaccine candidates

Fu, Yongshui, Zhang, Panli, Zhang, Yuming, Li, Tingting, Li, Jinfeng, Luo, Shengxue, Yang, Chan, Liang, Chaolan, Zeng, Jinfeng, Wang, Qi, Li, Chengyao, Liu, Bochao, Zhang, Ling, Allain, Jean-Pierre, Hou, Shuiping, Tang, Xi

2021

Overview

COVID-19 vaccines are being developed urgently worldwide. Here, we constructed two adenovirus vectored COVID-19 vaccine candidates of Sad23L-nCoV-S and Ad49L-nCoV-S carrying the full-length gene of SARS-CoV-2 spike protein. The immunogenicity of two vaccines was individually evaluated in mice. Specific immune responses were observed by priming in a dose-dependent manner, and stronger responses were obtained by boosting. Furthermore, five rhesus macaques were primed with 5 × 10 9 PFU Sad23L-nCoV-S, followed by boosting with 5 × 10 9 PFU Ad49L-nCoV-S at 4-week interval. Both mice and macaques well tolerated the vaccine inoculations without detectable clinical or pathologic changes. In macaques, prime-boost regimen induced high titers of 10 3.16 anti-S, 10 2.75 anti-RBD binding antibody and 10 2.38 pseudovirus neutralizing antibody (pNAb) at 2 months, while pNAb decreased gradually to 10 1.45 at 7 months post-priming. Robust T-cell response of IFN-γ (712.6 SFCs/10 6 cells), IL-2 (334 SFCs/10 6 cells) and intracellular IFN-γ in CD4 + /CD8 + T cell (0.39%/0.55%) to S peptides were detected in vaccinated macaques. It was concluded that prime-boost immunization with Sad23L-nCoV-S and Ad49L-nCoV-S can safely elicit strong immunity in animals in preparation of clinical phase 1/2 trials.

• Publisher: Taylor & Francis,Taylor & Francis Ltd,Taylor & Francis Group
• Subject: Adenoviruses / COVID-19 vaccines / human adenovirus 49 vector / mice and non-human primates / prime-boost vaccination / simian adenovirus 23 vector