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  • Pseudovirus Neutralization Assay Platform

Principle of pseudovirus neutralization assay

Entry of coronavirus like SARS-CoV and SARS-CoV-2 into host cells is mediated by the binding of the viral trimeric transmembrane spike (S) glycoprotein with human angiotensin-converting enzyme 2 (ACE2) on the host cell surface. The spike protein is the major target of neutralizing antibodies, and it is the focus of therapeutic drug and vaccine development.

To create a suitable model of simulating SARS-CoV-2 entry, a pseudotyped lentiviral vector is constructed with the envelope glycoprotein replaced by SARS-CoV-2 S protein. This model is able to accelerate the discovery of neutralizers like antibodies that disrupt the entry of virus into cells by blocking the binding of the S protein with ACE2 protein. With a reporter gene engineered in the pseudovirus, the neutralizing activity can be assessed with a great sensitivity and stability.

Application scenarios

Purpose of the assay: neutralization assay to screen or validate the activity of candidate molecules or immune serum
Phase to perform the assay: after binding or blocking assay; screening and validation before testing with pathogenic viruses
Expansion of the assay: in addition to antibody drugs, the assay could also be used for other entry inhibitors

Service highlights

  • Virus entry assay model: simulating the actual entry mechanism of SARS-CoV-2
  • High specificity: specifically screening candidates that block pseudovirus entry
  • High sensitivity: S/N ≥ 100, distinguishable neutralizing activities between different candidates
  • Fast delivery: 1-3 weeks*
  • Pseudovirus with SARS-CoV-2 Spike variant available
  • Extensible system, SARS-CoV-1 and multiple variants available; customized service available
  • Kits available for your in-house testing
  • *The TAT is for reference. The TAT will extend accordingly with increasing number of samples to test

Case study

Pseudovirus neutralization assay

Live virus neutralization assay


Sample Pseudovirus IC50 Live virus IC50
Ab #1 9.17 nM 17.95 nM

Figure 1. Comparable IC50 values of live virus and pseudovirus neutralization assay using the same sample.



Neutralization by ACE2-Fc

Figure 2. Positive control ACE2-Fc can effectively inhibit pseudovirus entry in a dose-dependent manner

Consistent IC50 in independent tests

Figure 3. Antibody candidates were screened for their ability to inhibit pseudovirus entry.



Neutralization by immunized mice serum

Figure 4. Immunized mouse serum can effectively inhibit pseudovirus entry

Principle of neutralization assay

Pseudovirus neutralization assay

Starting materials

  • ≥ 100 μg neutralizing antibody for single dose screening, or ≥ 200 μg for dose-response assay
  • supernatant with antibody ≥ 1 μg/mL, more than ≥ 500 μL (Optimization is needed for different culture media)
  • Serum samples from immunized animals. Human samples should be tested with pseudovirus neutralization kit
  • Small molecules, peptides or other candidate samples inhibiting virus entry
  • Pseudovirus and target cells for infection are provided by GenScript ProBio

Delivery: Neutralization assay report

QC standard: S/N ≥ 100

Turnaround time: 1-3 weeks*

*TAT may extend due to the number of samples.

Extensible platform for your SARS-CoV-2-related assays

Pseudovirus-related products

Available cell line for blocking and neutralization assays

Cell line QC TAT(week)
Hela/ACE2 single clone FACS
ELISA binding
Pseudovirus infection
1-2
HEK293/ACE2 single clone FACS
Pseudovirus infection
1-2
CHO-K1/SPIKE_SARS2 single clone FACS 1-2
HEK293T/SPIKE_SARS2 single clone FACS 1-2

Available pseudovirus neutralization kit for in-house tests

Product Cat. No. name Deliverable
Luciferase reporter kit SC2087A SARS-CoV-2 Pseudovirus Neutralization Assay kit_Luc reporter

    Components*:

  • R Pseudovirus:
  • 1 vial of Luc reporter or 2 vials of GFP reporter for a 96-well plate
  • 10^7-8 IFU
  • R Target cell:
  • 2 vials for a 96-well plate
  • 2 × 10^6 cells/vial (proliferation-incompetent)
  • R Positive neutralizing antibody for 1 dose curve:
  • for 1 dose curve
  • * Components can be purchased separately.

SC2087B SARS-CoV-2 D614G Pseudovirus Neutralization Assay kit_Luc reporter
SC2087C SARS-CoV-2 V367F Pseudovirus Neutralization Assay kit _Luc reporter
SC2087D SARS-CoV-2 W436R Pseudovirus Neutralization Assay kit _Luc reporter
SC2087E SARS-CoV-2 D364Y Pseudovirus Neutralization Assay kit _Luc reporter
GFP reporter kit SC2087F SARS-CoV-2 Pseudovirus Neutralization Assay kit _GFP reporter
SC2087G SARS-CoV-2 D614G Pseudovirus Neutralization Assay kit _ GFP reporter
SC2087H SARS-CoV-2 V367F Pseudovirus Neutralization Assay kit _ GFP reporter

Ready-to-use platform for your customized pseudovirus production

Please contact GenScript ProBio for details.