Intro to the Pseudovirus
It has been two years since the outbreak of coronavirus disease 2019 (COVID-19)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the cause of the pandemic and has only gotten more complex for scientists to study.
Studies of live SARS-CoV-2 are restricted to biosafety level 3 laboratories, which has made SARS-CoV-2 research inaccessible to the majority of research labs around the world. This can delay the development of vaccines and therapeutics against SARS-CoV-2. Finding alternative non-infectious methods to study the virus is required to expedite discoveries.
Pseudoviruses are recombinant viruses with their backbone and surface proteins derived from different viruses. Genes inside pseudoviruses are modified to remove any native surface protein expression but retain functional aspects of the virus making them invaluable research tools. An additional plasmid is then added to the viral code to express alternative surface proteins, producing a pseudovirus that can infect susceptible host cells but can only replicate intracellularly for a single round. As viral surface proteins play pivotal roles in gaining entry into host cells, the conformational structures of pseudo-viral surface proteins have high similarity to that of the native viral proteins; however, pseudoviruses have attenuated virulence compared with wild-type (WT) viruses, allowing them to be safely handled in biosafety level 2 laboratories. As a result, pseudoviruses are widely used for the study of cellular tropism, receptor recognition, drug discovery, and for developing and evaluating antibodies and vaccines.
- Safe in a BSL-2 environment
- Quantitative (luciferase) readout
- Compatible with high-throughput plate-based assays
- Quality-controlled production for use as a critical reagent
Pseudoviruses from ProSci
ProSci has developed SARS-CoV-2 pseudoviruses with a luciferase reporter allowing researchers to quickly build their own neutralization and inhibitor interaction assays. These pseudoviruses have been engineered to lack the appropriate coding for the virus to replicate.
Developed using an HIV lentivirus and pseudotyped with SARS-CoV-2 spike glycoproteins from variants of concern, the pseudovirus is expressed but lacks the appropriate coding to replicate. This makes pseudoviruses excellent research tools for labs operating under BSL-2 by offering an alternative to live-virus experimentation. Visit the full list of SARS-CoV-2 pseudoviruses.
- Chen, M., & Zhang, X.-E. (2021). Construction and applications of SARS-CoV-2 pseudoviruses: a mini review. In International Journal of Biological Sciences (Vol. 17, Issue 6, pp. 1574–1580). Ivyspring International Publisher. https://doi.org/10.7150/ijbs.59184