Virol J. 2022 Dec 9
Guochao Liao, Hungyan Lau, Zhongqiu Liu, Chinyu Li, Zeping Xu, Xiaoxiao Qi, Yu Zhang, Qian Feng, Runze Li, Xinyu Deng, Yebo Li, Qing Zhu, Sisi Zhu, Hua Zhou, Hudan Pan, Xingxing Fan, Yongchao Li, Dan Li, Liqing Chen, Bixia Ke, Zhe Cong, Qi Lv, Jiangning Liu, Dan Liang, Anan Li, Wenshan Hong, Linlin Bao, Feng Zhou, Hongbin Gao, Shi Liang, Bihong Huang, Miaoli Wu, Chuan Qin, Changwen Ke and Liang Liu
Products used in the paper Details Operation
AAV vector packaging The recombinant type 5 adenoviral-vectored SARSCoV- 2 (Accession Number: MN985325.1) vaccines encoding RBD domain (residues 319-541), RBD-plus domain (residues 319-583), S1 protein (residues 14-685), full-length of S protein (residues 14-1213) and NTD domain (residues 14-305 of the S protein N-terminal domain) of SARS-CoV-2 were produced by PackGene Biotech (Guangzhou, China). Briefly, rAAV5 packaging plasmids were transfected into HEK293T cells using PEI transfection reagent, according to the manufacturer’s protocol. The transfected cells and supernatants were harvested 72 h post transfection. rAAV5- vaccine was purified and titrated by real-time quantitative PCR. rAAV5-vaccine was adjusted to 10^12 GCs/mL in PBS and used for the following vaccinations. Request Quote

Research Field: Covid-related

Keywords: SARS-CoV-2, Vaccine, rAAV5, Neutralizing antibodies, Virus challenge

Routes of Administration: All animals were immunized with rAAV5-based vaccines or rAAV5-GFP (control group) via intramuscular (IM) injection in the hind leg or intranasal inoculation at a single dose (five to eight animals for each group).

Animal or cell line strain: Six weeks-old, 36 weeks-old female BALB/c mice and 6–8 weeks female Wistar rats

Abstract

The COVID-19 pandemic, caused by the SARS-CoV-2 virus and its variants, has posed unprecedented challenges worldwide. Existing vaccines have limited effectiveness against SARS-CoV-2 variants. Therefore, novel vaccines to match mutated viral lineages by providing long-term protective immunity are urgently needed. We designed a recombinant adeno-associated virus 5 (rAAV5)-based vaccine (rAAV-COVID-19) by using the SARS-CoV-2 spike protein receptor binding domain (RBD-plus) sequence with both single-stranded (ssAAV5) and self-complementary (scAAV5) delivery vectors and found that it provides excellent protection from SARS-CoV-2 infection. A single-dose vaccination in mice induced a robust immune response; induced neutralizing antibody (NA) titers were maintained at a peak level of over 1:1024 more than a year post-injection and were accompanied by functional T-cell responses. Importantly, both ssAAV- and scAAV-based RBD-plus vaccines produced high levels of serum NAs against the circulating SARS-CoV-2 variants, including Alpha, Beta, Gamma and Delta. A SARS-CoV-2 virus challenge showed that the ssAAV5-RBD-plus vaccine protected both young and old mice from SARS-CoV-2 infection in the upper and lower respiratory tracts. Whole genome sequencing demonstrated that AAV vector DNA sequences were not found in the genomes of vaccinated mice one year after vaccination, demonstrating vaccine safety. These results suggest that the rAAV5-based vaccine is safe and effective against SARS-CoV-2 and several variants as it provides long-term protective immunity. This novel vaccine has a significant potential for development into a human prophylactic vaccination to help end the global pandemic.

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