Optimization of Non-Coding Regions Improves Protective Efficacy of an mRNA SARS-CoV-2 Vaccine in Nonhuman Primates
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Abstract
The CVnCoV (CureVac) mRNA vaccine for SARS-CoV-2 has recently been evaluated in a phase 2b/3 efficacy trial in humans. CV2CoV is a second-generation mRNA vaccine with optimized non-coding regions and enhanced antigen expression. Here we report a head-to-head study of the immunogenicity and protective efficacy of CVnCoV and CV2CoV in nonhuman primates. We immunized 18 cynomolgus macaques with two doses of 12 ug of lipid nanoparticle formulated CVnCoV, CV2CoV, or sham (N=6/group). CV2CoV induced substantially higher binding and neutralizing antibodies, memory B cell responses, and T cell responses as compared with CVnCoV. CV2CoV also induced more potent neutralizing antibody responses against SARS-CoV-2 variants, including B.1.351 (beta), B.1.617.2 (delta), and C.37 (lambda). While CVnCoV provided partial protection against SARS-CoV-2 challenge, CV2CoV afforded robust protection with markedly lower viral loads in the upper and lower respiratory tract. Antibody responses correlated with protective efficacy. These data demonstrate that optimization of non-coding regions can greatly improve the immunogenicity and protective efficacy of an mRNA SARS-CoV-2 vaccine in nonhuman primates.
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SciScore for 10.1101/2021.08.13.456316: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics Field Sample Permit: All animal studies were conducted in compliance with all relevant local, state, and federal regulations and were approved by the Bioqual Institutional Animal Care and Use Committee (IACUC).
IACUC: All animal studies were conducted in compliance with all relevant local, state, and federal regulations and were approved by the Bioqual Institutional Animal Care and Use Committee (IACUC).Sex as a biological variable not detected. Randomization Animals and study design: 18 cynomolgus macaques were randomly assigned to three groups. Blinding Immunologic and virologic assays were performed blinded. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
… SciScore for 10.1101/2021.08.13.456316: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics Field Sample Permit: All animal studies were conducted in compliance with all relevant local, state, and federal regulations and were approved by the Bioqual Institutional Animal Care and Use Committee (IACUC).
IACUC: All animal studies were conducted in compliance with all relevant local, state, and federal regulations and were approved by the Bioqual Institutional Animal Care and Use Committee (IACUC).Sex as a biological variable not detected. Randomization Animals and study design: 18 cynomolgus macaques were randomly assigned to three groups. Blinding Immunologic and virologic assays were performed blinded. Power Analysis not detected. Cell Line Authentication not detected. Table 2: Resources
Antibodies Sentences Resources B cell immunophenotyping: Fresh PBMCs were stained with Aqua live/dead dye (Invitrogen) for 20 min, washed with 2% FBS/DPBS buffer, and suspended in 2% FBS/DPBS buffer with Fc Block (BD) for 10 min, followed by staining with monoclonal antibodies against CD45 (clone D058-1283, BUV805), CD3 (clone SP34.2, APC-Cy7), CD7 (clone M-T701, Alexa700), CD123 (clone 6H6, Alexa700), CD11c (clone 3.9, Alexa700), CD20 (clone 2H7, PE-Cy5), IgA (goat polyclonal antibodies, APC), IgG (clone G18-145, BUV737), IgM (clone G20-127, BUV396), IgD (goat polyclonal antibodies, PE), CD80 (clone L307.4, BV786), CD95 (clone DX2, BV711), CD27 (clone M-T271, BUV563), CD21 (clone B-ly4, BV605), CD14 (clone M5E2, BV570) and CD138 (clone DL-101, PE-CF594). CD45suggested: (BD Biosciences Cat# 564914, RRID:AB_2744401)CD3suggested: (GenWay Biotech Inc. Cat# GWB-220B7B, RRID:AB_10511043)CD7suggested: (BD Biosciences Cat# 741824, RRID:AB_2871159)CD123suggested: (BD Biosciences Cat# 751837, RRID:AB_2875808)CD11csuggested: (BioLegend Cat# 117331, RRID:AB_10900261)CD20suggested: (BD Biosciences Cat# 743611, RRID:AB_2741622)PE-Cy5), IgAsuggested: (Bioss Cat# bs-0645R-PE-Cy5, RRID:AB_11071475)IgMsuggested: (Creative Diagnostics Cat# DCABY-1319, RRID:AB_2493413)CD80suggested: (Thermo Fisher Scientific Cat# EPX140-15803-901, RRID:AB_2576106)CD95suggested: (BD Biosciences Cat# 741292, RRID:AB_2870823)CD27suggested: (BD Biosciences Cat# 748705, RRID:AB_2873109)CD21suggested: (BD Biosciences Cat# 740395, RRID:AB_2740125)CD14suggested: (BioLegend Cat# 301831, RRID:AB_10897803)CD138suggested: NoneIFN-γ enzyme-linked immunospot (ELISPOT) assay: ELISPOT plates were coated with mouse anti-human IFN-γ monoclonal antibody from BD Pharmingen at a concentration of 5 μg/well overnight at 4°C. anti-human IFN-γsuggested: NoneThe plates are washed a second time and incubated for 2 h with Streptavidin-alkaline phosphatase antibody from Southern Biotechnology (1 μg/mL). Streptavidin-alkaline phosphatasesuggested: NoneExperimental Models: Cell Lines Sentences Resources Briefly, the packaging plasmid psPAX2 (AIDS Resource and Reagent Program), luciferase reporter plasmid pLenti-CMV Puro-Luc (Addgene), and Spike protein expressing pcDNA3.1-SARS CoV-2 SΔCT of variants were co-transfected into HEK293T cells by lipofectamine 2000 (ThermoFisher). HEK293Tsuggested: NoneTo determine the neutralization activity of the plasma or serum samples from participants, HEK293T-hACE2 cells were seeded in 96-well tissue culture plates at a density of 1.75 x 104 cells/well overnight. HEK293T-hACE2suggested: RRID:CVCL_A7UK)Recombinant DNA Sentences Resources Briefly, the packaging plasmid psPAX2 (AIDS Resource and Reagent Program), luciferase reporter plasmid pLenti-CMV Puro-Luc (Addgene), and Spike protein expressing pcDNA3.1-SARS CoV-2 SΔCT of variants were co-transfected into HEK293T cells by lipofectamine 2000 (ThermoFisher). psPAX2suggested: RRID:Addgene_12260)pLenti-CMVsuggested: NonepcDNA3.1-SARSsuggested: NoneThe gene fragment was subsequently cloned into a pcDNA3.1+ expression plasmid using restriction site cloning (Integrated DNA Technologies). pcDNA3.1+suggested: RRID:Addgene_117272)Software and Algorithms Sentences Resources Subsequent analyses were performed using FlowJo software (Treestar, v.9.9.6). FlowJosuggested: (FlowJo, RRID:SCR_008520)Statistical analyses: Statistical analyses were performed using GraphPad Prism (version 9.0) software (GraphPad Software) and comparison between groups was performed using a two-tailed nonparametric Mann-Whitney U t test. GraphPad Prismsuggested: (GraphPad Prism, RRID:SCR_002798)GraphPadsuggested: (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: We did not find any issues relating to colormaps.
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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