A Cape Town company has partnered others overseas to produce a plant-based antigen that could possibly be used in rapid-diagnostic test kits for the virus. According to a report in The Times, these tests differ from the polymerase chain reaction (PCR) tests being done at scale in South Africa.
PCR tests for COVID-19 involve a nasal swab that is sent to a laboratory for testing. There, technicians search for the active presence of the virus, which will show if the patient is still infectious. Rapid diagnostic tests (or serology tests), on the other hand, check for the presence of antibodies in your blood or sputum to see if you’ve had an immune response to the virus, but they do not show if you’re still infectious.
Cape Bio Pharms, a spin-off company of the biopharming research unit at the University of Cape Town, partnered international biotech companies in the Plants Against Corona initiative. “We are working towards developing antigens and antibodies for late-stage serology tests that detect antibodies in a patient’s blood,” Cape Bio Pharms co-founder Tamlyn Shaw is quoted in the report as saying. The company sourced the gene sequences for SARS-CoV-2 to develop antigen constructs that could speed up production of antigens, globally.
According to Professor Wolfgang Preiser, a virology expert at the University of Stellenbosch, “antibody tests will have a role to play” in the future. But not all of them were reputable. “We know that many of the tests being marketed overseas are not good, so before one launches into using them it will be important to assess their performance,” he said.
Preiser said the use of antibody tests to declare someone “safe” was premature. “Neither do we know a lot about immunity … but the good news is that so much is going on in this field that we should learn more pretty soon,” he said in the report.
[link url="https://www.timeslive.co.za/news/sci-tech/2020-05-06-cape-company-looks-to-tobacco-plants-cousin-in-search-for-covid-19-antigen/"]Full report in The Times[/link]