A team from QIMR Berghofer Medical Research Institute, in collaboration with La Trobe University, The University of Queensland, and Monash University, has found exposure to a common cold virus may help prepare the body’s immune system to respond to SARS-CoV-2.
The study is one of the first to demonstrate how the body’s ‘killer’ T cells, which specialise in killing infected cells, could use their memory of fighting other coronaviruses to respond more quickly to SARS-CoV-2 – the coronavirus that causes COVID-19.
Joint-lead researcher Associate Professor Corey Smith, who heads QIMR Berghofer’s Translational and Human Immunology Group, said the team found this response occurred in people who had previously recovered from a strain of the common cold, called the beta coronavirus, even though they had never before been exposed to the COVID-19-causing virus.
“T cells are the immune cells that recognise and destroy cells infected with SARS-CoV-2. They typically mount an early response, even before the body starts to produce antibodies.
“Most importantly, T cells develop a lasting memory of viral infections, which enables the immune system to respond rapidly in the event of reinfection,” Associate Professor Smith said.
“This study confirms there is T cell cross-recognition of this beta coronavirus, which causes the common cold, and of SARS-CoV-2. We hope this significant finding will have implications for global understanding of how our immune system’s memory might be harnessed to tackle COVID-19-diseased cells.”
Co-lead researcher Professor Stephanie Gras, from the La Trobe Institute for Molecular Science, said the research findings will also help scientists better understand how immune cells recognise newly emerging SARS-CoV-2 variants.
“We are the first to demonstrate the similarities in chemical structure between both the SARS-CoV-2 and beta-coronavirus strains and how this results in the ability of killer T cells to recognise and respond to both,” Professor Gras said.
“A lot of headway is being made in the battle against COVID-19 with vaccine rollouts currently underway, but the ongoing emergence of new variants has highlighted the importance of continuing to identify new ways of targeting this disease.”
QIMR Berghofer researcher Dr Katie Lineburg said the team studied blood from 37 recovered COVID-19 patients to understand the biology behind why some people have better T cell immunity to the virus than others.
“Initially we looked at the T cell responses in a larger group of people shortly after they recovered from COVID-19 and identified that a majority of them showed a strong immune response to a specific portion of the SARS-CoV-2 virus called the nucleocapsid protein,” Dr Lineburg said.
“We were able to show that because the genetic sequence of this nucleocapsid protein is very similar between SARS-CoV-2 and a common beta coronavirus, the memory T cells targeting each virus are also capable of recognising the other and producing the molecules needed to kill an infected cell.
“We’re hopeful that identifying which parts of the virus trigger an immune response will help us to develop a T cell immunotherapy that could be used to treat patients who don’t respond well to existing treatments.”
The researchers are now investigating T cell responses in people who have been vaccinated, with the aim to understand how vaccinated individuals establish memory T cell responses against the vaccine-target spike protein.
The new baseline studies will allow the team to investigate a range of immune responses including how these people’s T cells cross-recognise other SARS-CoV-2 variants.
Australians who wish to participate in the study on COVID-19 disease and COVID-19 vaccination should contact co-lead investigator Professor Stephanie Gras (S.firstname.lastname@example.org).
The QIMR Berghofer research was jointly funded by QIMR Berghofer’s philanthropic donors, including Mr Clive Berghofer AM and the Brazil Family Foundation, as well as the Federal Government’s Medical Research Future Fund.
The research findings are published and can be accessed on the Immunity journal website. The DOI is: https://doi.org/10.1016/j.immuni.2021.04.006
Source: QIMR Berghofer Medical Research Institute