‘Other research groups, including our Danish partner, are developing other proteins,’ says researcher Gorben Pijlman. ‘The protein that performs best in the tests will be used in the coronavirus vaccine.’
Spikes
A coronavirus has a rough surface, with proteins sticking out of it. The viruses need these spikes, as they are called, to penetrate our cells, where they make us ill. Pijlman is going to create synthetic versions of those proteins that will prime the body’s immune system to deactivate the virus. ‘If we inject the protein, the body will recognize it as foreign and manufacture antibodies and memory cells. That is the vaccine. We show our immune system the picture it needs to remember, as it were. If we then catch the coronavirus, the body quickly makes antibodies that deactivate the virus.’
Baculovirus
The Virology chair group has a lot of experience with culturing these kinds of complex virus proteins in insect cells. Pijlman starts by selecting a fragment of the coronavirus’ DNA code that makes the spike proteins with which the virus penetrates our cells. He then introduces this DNA into a baculovirus. This baculovirus, which is harmless to humans, then infects cultured cells from an insect – in this case a moth – and stimulates these cells to produce the protein in question. Eventually, these insect cells are put into a bioreactor, in which the spikes can be produced in larger quantities.
Two months
Pijlman is now in the early stages of producing these proteins, working with a PhD student and a lab technician on cloning the fragment of DNA from the coronavirus. He hopes to have an active protein in two months. There isn’t a vaccine yet at that point, though. ‘We’ll have to test the protein extensively. We first have to find out if it is effective. In other words: does it get our immune system working sufficiently? And secondly, is the vaccine that uses this protein safe? We need to test that thoroughly on animals – mice, perhaps – before it can be licensed for use.’
The Virology group has made comparable complex proteins that can be used as vaccines before. In 2013, for example, the Wageningen group produced an efficient prototype vaccine against the chikungunya virus.
The Wageningen virologists are part of a European consortium led by the Danish company Expres2ion Biotechnologies. That group has received funding from the European Commission to develop a vaccine against the SARS-CoV-2 virus.