The key properties of the spikes of SARS-CoV-2, the virus which causes Covid-19, are consistent with those of several laboratory-developed protein spikes, designed to mimic the infectious virus, a new international study has found.The manufacture of protein "spikes" is a central component in designing serological tests and vaccines to protect against Covid-19. These recombinant spikes closely mimic those sticking out of the surface of the infectious virus and trigger the body's immune system into action.Laboratory manufactured spikes are also used for serological testing (also referred to as antibody testing) and as research reagents.The new study, led by researchers at the University of Southampton in the UK, showed that viral spikes manufactured through different methods in laboratories across the globe are highly similar and provide reassurance that the spike can be robustly manufactured with minimal variations between laboratories."Over the last year we have seen vaccines developed around the world at an unprecedented rate and the rapid development, and validation, of recombinant proteins have been fundamental to that success story," said lead researcher Max Crispin, Professor of Glycobiology at the varsity.
The spikes on the SARS-CoV-2 virus are coated in sugars, known as glycans, which they use to disguise themselves from the human immune system. The abundance of these glycans has the potential to create significant discrepancies between studies that use different recombinant spikes.For the study, the team examined the glycan coatings on recombinant spikes developed in five laboratories around the world and compared them to those on the spikes of the infectious virus.In April 2020, Crispin and his team had mapped the glycan coating of the SARS-CoV-2 spike for the first time. In the present study, they extended their analysis to examine recombinant spikes developed in laboratories at the Amsterdam University Medical Centre, Harvard Medical School, the University of Oxford, and the Swiss company ExcellGene. All the different batches of spike protein were shown to mimic key features of the glycosylation of inactivated virions analysed at Tsinghua University, China."The ability to produce mimics of the SARS-CoV-2 spike protein with high fidelity at many different laboratories, all of which recapitulate the glycan signatures of the authentic virus, is of significant benefit for vaccine design, antibody testing and drug discovery," Crispin said.