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By Liam Mannix
August 20, 2020 — 6.02pm
Evidence is emerging worldwide showing between 20 and 50 per cent of people who have never been exposed to COVID-19 have immune cells that can recognise and react to the virus.
The discovery of T cell cross-reactivity has excited immunologists, who hope it could explain some of the mysteries that surround the virus, such as why some people get so much sicker than others.
But scientists caution that it is not yet clear what the discovery means for human health.
Australian National University's head of immunology and infectious diseases, Professor David Tscharke, said: "It's the good, the bad and the ugly – it could help, it could do nothing, or it could make COVID-19 worse."
Professor Tscharke said the cross-reactive T cells might help to fight off the virus, or they might get in the way of the immune system, making the disease worse, a phenomenon known as "original antigenic sin".
... SARS-CoV-2, the virus that causes COVID-19, shares much of its genetic code, including many of its proteins, with four coronaviruses in frequent circulation among humans.
Dr Corey Smith, head of the translational and human immunology laboratory at the QIMR Berghofer Medical Research Institute, said some sections of the genetic codes were virtually identical.
They cause the common cold and are extremely common – more than 90 per cent of people have been exposed to them.
Scientists suspect some people who have been exposed to these viruses develop T cells that can also target SARS-CoV-2.
Monash University's head of microbiology, Professor Stephen Turner, said that in the best-case scenario, cross-reactive T cells do offer some protection.
...
August 20, 2020 — 6.02pm
Evidence is emerging worldwide showing between 20 and 50 per cent of people who have never been exposed to COVID-19 have immune cells that can recognise and react to the virus.
The discovery of T cell cross-reactivity has excited immunologists, who hope it could explain some of the mysteries that surround the virus, such as why some people get so much sicker than others.
But scientists caution that it is not yet clear what the discovery means for human health.
Australian National University's head of immunology and infectious diseases, Professor David Tscharke, said: "It's the good, the bad and the ugly – it could help, it could do nothing, or it could make COVID-19 worse."
Professor Tscharke said the cross-reactive T cells might help to fight off the virus, or they might get in the way of the immune system, making the disease worse, a phenomenon known as "original antigenic sin".
... SARS-CoV-2, the virus that causes COVID-19, shares much of its genetic code, including many of its proteins, with four coronaviruses in frequent circulation among humans.
Dr Corey Smith, head of the translational and human immunology laboratory at the QIMR Berghofer Medical Research Institute, said some sections of the genetic codes were virtually identical.
They cause the common cold and are extremely common – more than 90 per cent of people have been exposed to them.
Scientists suspect some people who have been exposed to these viruses develop T cells that can also target SARS-CoV-2.
Monash University's head of microbiology, Professor Stephen Turner, said that in the best-case scenario, cross-reactive T cells do offer some protection.
...
