Single-shot rAAV5-based Vaccine Provides Long-term Protective Immunity against SARS-CoV-2 and Its Variants

Abstract

The COVID-19 pandemic and the SARS-CoV-2 with its variants have posed unprecedented challenges worldwide. Existing vaccines have limited effectiveness against the SARS-CoV-2 variants. Therefore, novel vaccines to match current mutated viral lineages with long-term protective immunity are urgently in demand. In the current study, we for the first time designed a recombinant Adeno-Associated Virus 5 (rAAV5)-based vaccine named as rAAV-COVID-19 vaccine (Covacinplus) by using RBD-plus of spike protein with both the single-stranded and the self-complementary AAV5 delivering vectors (ssAAV5 and scAAAV5), which provides excellent protection from SARS-CoV-2 infection. A single dose vaccination induced the strong immune response against SARS-CoV-2. The induced neutralizing antibodies (NAs) titers were maintained at a high peak level of over 1:1024 even after more than one year of injection and accompanied with functional T-cells responses in mice. Importantly, both ssAAV- and scAAV-based RBD-plus vaccines exhibited high levels of serum NAs against current circulating variants including variants Alpha, Beta, Gamma and Delta. SARS-CoV-2 virus challenge test showed that ssAAV5-RBD-plus vaccine protected both young and old age mice from SARS-CoV-2 infection in the upper and the lower respiratory tracts. Moreover, whole genome sequencing demonstrated that AAV vector DNA sequences were not found in the genome of the vaccinated mice after one year vaccination, demonstrating excellent safety of the vaccine. Taken together, this study suggests that rAAV5-based vaccine is powerful against SARS-CoV-2 and its variants with long-term protective immunity and excellent safety, which has great potential for development into prophylactic vaccination in human to end this global pandemic.

SciScore for 10.1101/2021.08.23.456471: (What is this?)

Please note, not all rigor criteria are appropriate for all manuscripts.

Table 1: Rigor

Ethics	IACUC: The research was approved by the Guangzhou University of Chinese Medicine Animal Care and Use Committee.
Sex as a biological variable	Animals in the experiments: 6 weeks-old, 36 weeks-old female BALB/c mice and 6-8 weeks female Wistar rats were purchased from the Laboratory Animal Center of Southern Medical University (Guangdong, China).
Randomization	not detected.
Blinding	not detected.
Power Analysis	not detected.
Cell Line Authentication	not detected.

Table 2: Resources

Experimental Models: Cell Lines
Sentences	Resources
Viruses and cells: Vero E6 cells (CRL-1586, American Type Culture Collection (ATCC) and HEK293 cells were cultured at 37℃ in Dulbeccos Modified Eagle medium (DMEM) supplemented …

SciScore for 10.1101/2021.08.23.456471: (What is this?)

Please note, not all rigor criteria are appropriate for all manuscripts.

Table 1: Rigor

Ethics	IACUC: The research was approved by the Guangzhou University of Chinese Medicine Animal Care and Use Committee.
Sex as a biological variable	Animals in the experiments: 6 weeks-old, 36 weeks-old female BALB/c mice and 6-8 weeks female Wistar rats were purchased from the Laboratory Animal Center of Southern Medical University (Guangdong, China).
Randomization	not detected.
Blinding	not detected.
Power Analysis	not detected.
Cell Line Authentication	not detected.

Table 2: Resources

Experimental Models: Cell Lines
Sentences	Resources
Viruses and cells: Vero E6 cells (CRL-1586, American Type Culture Collection (ATCC) and HEK293 cells were cultured at 37℃ in Dulbeccos Modified Eagle medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 10 mM HEPES pH 7.4, 1 mM sodium pyruvate, 1X non-essential amino acids, and 100 U/ml of penicillin streptomycin.	HEK293 suggested: None
Briefly, rAAV5 packaging plasmids were transfected into HEK293T cells using PEI transfection reagent, according to the manufacturer’s protocol.	HEK293T suggested: CCLV Cat# CCLV-RIE 1018, RRID:CVCL_0063)
Vero E6 cells were seeded at 104/well in 96-well culture plates and cultured at 37°C to form a monolayer.	Vero E6 suggested: None
Experimental Models: Organisms/Strains
Sentences	Resources
Animals in the experiments: 6 weeks-old, 36 weeks-old female BALB/c mice and 6-8 weeks female Wistar rats were purchased from the Laboratory Animal Center of Southern Medical University (Guangdong, China).	BALB/c suggested: None Wistar suggested: RRID:MGI:5657554)
Recombinant DNA
Sentences	Resources
All animals were immunized with rAAV5-based vaccines or rAAV5-GFP via i.m in the hind leg or via intranasal inoculation at a single dose (five to eight animals for each group).	rAAV5-GFP suggested: None
Briefly, rAAV5 packaging plasmids were transfected into HEK293T cells using PEI transfection reagent, according to the manufacturer’s protocol.	rAAV5 suggested: None
Software and Algorithms
Sentences	Resources
Statistical significance among different vaccination groups was calculated by the student t test using Stata statistical software (GraphPad Prism 7).	Stata suggested: (Stata, RRID:SCR_012763) GraphPad suggested: (GraphPad Prism, RRID:SCR_002798)

Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

Results from TrialIdentifier: No clinical trial numbers were referenced.

Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

Results from JetFighter: Please consider improving the rainbow (“jet”) colormap(s) used on pages 16, 17 and 21. At least one figure is not accessible to readers with colorblindness and/or is not true to the data, i.e. not perceptually uniform.

Results from rtransparent:

Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
No protocol registration statement was detected.

Results from scite Reference Check: We found no unreliable references.

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Single-shot rAAV5-based Vaccine Provides Long-term Protective Immunity against SARS-CoV-2 and Its Variants

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