SARS-CoV-2 Spike-pseudovirus Based Neutralization Assay

Creative Biolabs, as the leading biomedical CRO in the industry, has successfully helped thousands of researchers complete the development of drugs and vaccines. These achievements are inseparable from our excellent R&D platform and experienced technicians. In the development of COVID-19 drugs and vaccines, one of the most important evaluation indicators is to detect the neutralization ability of the therapeutics to SARS-CoV-2 virus. To this end, we have developed the pseudovirus corresponding to SARS-CoV-2 and provided related pseudovirus-based neutralization test services.

Pseudovirus’ Role in Evaluating Vaccine / Drug Neutralization Ability

The ability of vaccines or drugs to neutralize viruses is an important sign of their efficacy in preventing or treating viral diseases. Under normal circumstances, the vaccine or drug can be directly incubated with live virus in vitro, and then the virus' ability to infect cells can be observed to evaluate its virus neutralizing ability. However, for the highly infectious SARS-CoV-2, operations related to live viruses must be performed under BSL-3 conditions, which greatly limits the development process of COVID-19 vaccines and drugs. Pseudoviruses have the proteins necessary for live viruses to infect cells, but lack the nucleic acid of the virus and cannot replicate in the body. Therefore, they are highly safe and versatile, making them ideal tools for studying the ability of vaccines and drugs to neutralize viruses.

Fig.1 Principle of spike-pseudovirus based neutralization assay.

SARS-CoV-2 Spike-pseudovirus Based Neutralization Assay

SARS-CoV-2 has four structural proteins: spike protein (S), membrane protein (M), envelope protein (E), and nucleocapsid protein (N). Among them, S protein is related to virus attachment and entry into target cells and is considered to be a key protein to start the process of virus infection. In addition, during SASR-CoV-2 infection, S protein plays an important role in inducing protective humoral and cellular immune responses. Therefore, S protein has become the most attractive target for the development of SARS-CoV-2 vaccines and drugs.

Creative Biolabs uses HIV-1 containing a luciferase reporter gene as a backbone plasmid, and co-transfects 293 cells with a plasmid expressing the SARS-CoV-2 spike protein to package a spike-pseudovirus with SARS-CoV- 2 spike expressing on its surface and containing luciferase reporter gene inside. In combination with our proprietary ACE2-293T clonal cell-line, Creative Biolabs has successfully evaluated the neutralizing ability of antibodies and serum.

Fig.2 Workflow for SARS-CoV-2 Spike-pseudovirus based neutralization assay

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