ABSTRACT
The COVID-19 pandemic continues to wreak havoc as worldwide SARS-CoV-2 infection, hospitalization, and death rates climb unabated. Effective vaccines remain the most promising approach to counter SARS-CoV-2. Yet, while promising results are emerging from COVID-19 vaccine trials, the need for multiple doses and the challenges associated with the widespread distribution and administration of vaccines remain concerns. Here, we engineered the coat protein of the MS2 bacteriophage and generated nanoparticles displaying multiple copies of the SARS-CoV-2 spike (S) protein. The use of these nanoparticles as vaccines generated high neutralizing antibody titers and protected Syrian hamsters from a challenge with SARS-CoV-2 after a single immunization with no infectious virus detected in the lungs. This nanoparticle-based vaccine platform thus provides protection after a single immunization and may be broadly applicable for protecting against SARS-CoV-2 and future pathogens with pandemic potential.
Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/immunology , COVID-19/prevention & control , Pandemics , SARS-CoV-2 , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Drug Delivery Systems , Female , Humans , Immunization/methods , Levivirus/genetics , Levivirus/immunology , Mesocricetus , Microscopy, Electron, Transmission , Models, Animal , Nanoparticles/administration & dosage , Nanoparticles/ultrastructure , Nanotechnology , Pandemics/prevention & control , Protein Engineering , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/administration & dosage , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Combined/administration & dosage , Vaccines, Combined/genetics , Vaccines, Combined/immunology , Vaccines, Virus-Like Particle/administration & dosage , Vaccines, Virus-Like Particle/genetics , Vaccines, Virus-Like Particle/immunologyABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a huge threat to public health. Viral nucleic acid testing is the diagnostic gold standard and can play an important role in the prevention and control of this infection. In this study, bacteriophage MS2 virus-like particles encapsulating specific RNA sequences of SARS-CoV-2 and other coronaviruses were prepared by genetic engineering. The assessment panel, consisting of four positive samples with concentrations of 2.8, 3.5, 4.2, and 4.9 log10 copies/mL and five negative samples with other human coronaviruses, was prepared and distributed to evaluate the accuracy of routine viral RNA detection. Results of 931 panels from 844 laboratories were collected. The overall percentage agreement, positive percentage agreement (PPA), and negative percentage agreement, defined as the percentage of agreement between the correct results and total results submitted for all, positive, and negative samples were 96.8% (8109/8379), 93.9% (3497/3724), and 99.1% (4612/4655), respectively. For samples with concentrations of 4.9 and 4.2 log10 copies/mL, the PPAs were >95%. However, for 3.5 and 2.8 log10 copies/mL, the PPAs were 94.6% (881/931) and 84.9% (790/931), respectively. For all negative samples, the negative percentage agreement values were >95%. Thus, most laboratories can reliably detect SARS-CoV-2. However, further improvement and optimization are required to ensure the accuracy of detection in panel members with lower concentrations of viral RNA.
Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , Molecular Diagnostic Techniques/methods , SARS-CoV-2/genetics , Humans , Levivirus/genetics , Nucleic Acid Amplification Techniques , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Sensitivity and SpecificityABSTRACT
BACKGROUND: The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) has prompted a need for mass testing to identify patients with viral infection. The high demand has created a global bottleneck in testing capacity, which prompted us to modify available resources to extract viral RNA and perform reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) to detect SARS-COV-2. OBJECTIVES: Report on the use of a DNA extraction kit, after modifications, to extract viral RNA that could then be detected using an FDA-approved SARS-COV-2 RT-qPCR assay. MATERIALS AND METHODS: Initially, automated RNA extraction was performed using a modified DNA kit on samples from control subjects, a bacteriophage, and an RNA virus. We then verified the automated extraction using the modified kit to detect in-lab propagated SARSCOV-2 titrations using an FDA approved commercial kit (S, N, and ORF1b genes) and an in-house primer-probe based assay (E, RdRp2 and RdRp4 genes). RESULTS: Automated RNA extraction on serial dilutions SARS-COV-2 achieved successful one-step RT-qPCR detection down to 60 copies using the commercial kit assay and less than 30 copies using the in-house primer-probe assay. Moreover, RT-qPCR detection was successful after automated RNA extraction using this modified protocol on 12 patient samples of SARS-COV-2 collected by nasopharyngeal swabs and stored in viral transport media. CONCLUSIONS: We demonstrated the capacity of a modified DNA extraction kit for automated viral RNA extraction and detection using a platform that is suitable for mass testing. LIMITATIONS: Small patient sample size. CONFLICT OF INTEREST: None.