Prime-boost vaccination of mice and rhesus macaques with two novel adenovirus vectored COVID-19 vaccine candidates. Issue 1 (1st January 2021)

• Record Type: Journal Article
• Authors: Luo, Shengxue; Zhang, Panli; Liu, Bochao; Yang, Chan; Liang, Chaolan; Wang, Qi; Zhang, Ling; Tang, Xi; Li, Jinfeng; Hou, Shuiping; Zeng, Jinfeng; Fu, Yongshui; Allain, Jean-Pierre; Li, Tingting; Zhang, Yuming; Li, Chengyao
• Is Part Of: Emerging microbes & infections. Volume 10:Issue 1(2021)
• Page Start: 1002
• Page End: 1015
• Publication Date: 2021-01-01
• Subjects: COVID-19 vaccines -- simian adenovirus 23 vector -- human adenovirus 49 vector -- prime-boost vaccination -- mice and non-human primates; Medical microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.9041
• DOI: 10.1080/22221751.2021.1931466
• Languages: English
• ISSNs: 2222-1751

Abstract

ABSTRACT : 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.