Comprehensive Solutions to Accelerate SARS-CoV-2 Research

COVID-19 Services and Products

The impact that the COVID-19 pandemic has had worldwide is of unprecedented proportions, with over 280 million infected and 5.4 million deaths in 224 countries and areas.

From diagnostics to drug discovery and vaccine development, GenScript has developed a comprehensive range of products and services that scientists can use to accelerate COVID-19/SARS-CoV-2 research and development.

*Data current as of 27/12/2021

Services and Products

• Basic knowledge of SARS-CoV-2 detecion

  How to detect the SARS-CoV-2 virus?

  

  Figure from: Cryo-EM image of
  BetaCoV2019-2020.Courtesy:
  IVDC, China CDC

  On January 21, 2020, the U.S. Centers for Disease Control and Prevention (CDC) reported the first case in the United States of the new coronavirus. The arrival of new SARS-like coronavirus in U.S. heightens concerns about global spread after the infection cases reported in Thailand, Japan, South Korea and Taiwan. Meanwhile, a panel of Chinese health experts confirmed that the new virus is able to spread between people, which indicates it could be much harder to control.

  Via next generation sequencing (NGS) of cultured virus or samples from several pneumonia patients, the etiologic agent responsible for the pneumonia cases has been identified as a novel betacoronavirus (in the same family as SARS-CoV and MERS-CoV). Electron microscopy revealed the virus is a coronavirus with a characteristic crown morphology.

  The genome sequence of this betacoronavirus is crucial to develop specific diagnostic tests and to identify potential intervention options. Full genome sequence data from the viruses have been released and are available on NCBI (https://www.ncbi.nlm.nih.gov/nuccore/MN908947 ). Working directly from sequence information, a few laboratories developed several genetic amplification (PCR) assays to detect the novel coronaviruses. A few diagnostic kits developed by commercial companies, using the real-time PCR (RT-PCR) assay have been put to use rapidly. The timely emergence of detection methods is also one reason for the sharp rise in the number of confirmed cases.

  Principle of novel coronavirus detection

  The virus detection method can be basically illustrated as below.

  

  Step 1:

  Isolate the novel coronavirus (2019-nCoV) from the patients and sequence its genome.

  

  Step 2:

  Compare the genome sequence of 2019-nCoV with human genome to find out the specific sequence in the virus genome.

  

  Step 3:

  Design PCR amplification primers and fluorescent probe primers for detecting the specific sequences identified in step 2.

  

  Step 4:

  Extract RNA from suspected individual’s serum, and convert the RNA into cDNA. The cDNA is then used as template and mixed with the PCR primers and probes for amplification. If the fluorescence signal increases rapidly and Ct value is less than 37, it can be determined as positive; If there’s no fluorescence detected, or the fluorescence signal grows slowly and Ct value finally ends up above 40, it can be determined as negative.

• How Does SARS-CoV-2 Break Into Human Cells?

  To better understand the initial step of viral infection, we have to look at the structure of the coronavirus. It is composed of four structural proteins: spike (S), envelope (E), membrane (M) and nucleocapsid (N) proteins. The culprit behind the initial step of infection is the SARS-CoV-2 S protein, a homotrimeric S glycoprotein, containing a S1 subunit and S2 subunit in each monomer. The virus uses the receptor-binding domain (RBD) in the S1 subunit to bind to the angiotensin-converting enzyme 2 (ACE2) receptor on nonimmune cells and fuses the viral and host membranes via the S2 subunit. To further understand this interaction, Yu, J. et al.1 used X-ray crystallography to resolve the molecular structure of the RBD bound to the ACE2 receptor. They found that the sequence of the receptor-binding motif (RBM) within the RBD of the S1 subunit binds and cradles the lower bottom half of the N-terminal helix of ACE2. This realization offers scientists a specific target to develop more effective therapeutic neutralizing antibodies and helps in designing vaccines that can efficiently induce virus-specific neutralizing antibodies. Furthermore, the immunogenic RBD is widely used for the development of in vitro diagnostic assays aimed at determining previous exposure to SARS-CoV-2.

  

  Figure 1: Illustration of virus entering the body and interacting with the host cell.

  

  Figure 2: (a) The topology of the S protein (b) SARS-CoV-2 RBD sequence and structure (highlighted in red is the RBM sequence). Figure reproduced from Yu, J. et al.1

  Reference:

  Lan, J., Ge, J., Yu, J. et al. Structure of the SARS-CoV-2 spike receptor-binding domain bound to the ACE2 receptor. Nature 581, 215–220 (2020). https://doi.org/10.1038/s41586-020-2180-5

• Basic knowledge of SARS-CoV-2 surrogate virus neutralization test (sVNT)
  

  A new coronavirus, SARS-CoV-2, has recently emerged to cause a human pandemic. There is an urgent need for a robust serological test to detect neutralizing antibodies to SARS-CoV-2. Validated serologic assays are important for contact tracing, identifying the viral reservoir and epidemiological studies.

  There are two types of antibody tests that aim for detecting COVID-19 infection with sufficient specificity and sensitivity. The first type is the virus neutralization test (VNT) which detects neutralizing antibodies (NAbs) in a patient’s blood. VNT requires handling live SARS-CoV-2 in a specialized biosafety level 3 (BSL3) containment facility which is tedious and time consuming, taking 2-4 days to complete. Pseudovirus-based virus neutralization test (pVNT) is similar, but still requires the use of live viruses and cells although handled in a BSL2 laboratory.

  All other assays, such as ELISA and lateral flow rapid tests, represent the second assay type which detect only binding antibodies, and not Nab.

  Professor Lin-Fa Wang’s lab at Duke-NUS Medical School established a Surrogate virus neutralization test (sVNT) which detects NAbs, but without the need to use any live virus or cells and can be completed in 1-2 hours in a BSL2 lab. Using purified receptor binding domain (RBD) protein from the viral spike (S) protein and the host cell receptor ACE2, the test is designed to mimic the virus-host interaction by direct protein-protein interaction in a test tube or an ELISA plate well. This highly specific interaction can then be neutralized, i.e., blocked by highly specific Nabs in patient or animal sera in the same manner as in a conventional VNT.

Discoveries on SARS-CoV-2 from Our Customers

Since the outbreak of COVID-19 pandemic, the scientists over the world have been dedicated to studying the underlying molecular mechanism of SARS-CoV-2 infection. They constructed SARS-CoV-2 plasmid clone which can be used to evaluate the antivirals activities of functional protein materials and furtherly as key reagent for the coronavirus study (i.e., anti-virus antibody detection). Some papers reported the structure of SARS-CoV-2 proteins especially spike protein, helping researchers develop efficient detection assay approaches.

To date, over 97 publications on SARS-CoV-2 have cited and acknowledged GenScript for high quality services and products provided to accelerate the coronavirus research covering diagnostic detection reagents development, SAR-CoV-2 vaccine and therapeutics discovery. We are proud to help the global scientific community from 100+ laboratories in 12 countries, and the human population by making research easy with our sophisticated technologies.

Connect with MolecularCloud for the latest information on SARS-CoV-2.

Resources

WHO Guidance

On 17 January 2020, WHO provided interim guidance to laboratories and stakeholders involved in laboratory testing of patients who meet suspected case of pneumonia associated with the 2019 novel coronavirus.

• Laboratory testing for 2019 novel coronavirus (2019-nCoV) in suspected human cases.

Available Protocols

Diagnostic detection of Wuhan coronavirus 2019 by real-time RT-PCR – Charité, Berlin Germany (pdf)

Detection of 2019 novel coronavirus (2019-nCoV) in suspected human cases by RT-PCR – Hong Kong University (pdf)

China CDC Primers and probes for detection 2019-nCoV

SARS-CoV-2 qRT-PCR detection assay-1 step-1 plex Manual (pdf)

GenScript COVID-19 detection tech notes (pdf)