T cells from common colds cross-protect against infection with SARS-CoV-2

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 A new study, published in Nature Communications and led by Imperial College London researchers, provides the first evidence of a protective role for these T cells. While previous studies have shown that T cells induced by other coronaviruses can recognise SARS-CoV-2, the new study examines for the first time how the presence of these T cells at the time of SARS-CoV-2 exposure influences whether someone becomes infected.

The researchers also say their findings provide a blueprint for a second-generation, universal vaccine that could prevent infection from current and future SARS-CoV-2 variants, including Omicron.

Dr Rhia Kundu, first author of the study, from Imperial’s National Heart & Lung Institute, says: “Being exposed to the SARS-CoV-2 virus doesn’t always result in infection, and we’ve been keen to understand why. We found that high levels of pre-existing T cells, created by the body when infected with other human coronaviruses like the common cold, can protect against COVID-19 infection.

“While this is an important discovery, it is only one form of protection, and I would stress that no one should rely on this alone. Instead, the best way to protect yourself against COVID-19 is to be fully vaccinated, including getting your booster dose.”

The study began in September 2020 when most people in the UK had neither been infected nor vaccinated against SARS-CoV-2. It included 52 people who lived with someone with PCR-confirmed SARS-CoV-2 infection and who had therefore been exposed to the virus. The participants did PCR tests at the outset and 4 and 7 days later, to determine if they developed an infection.

Blood samples from the 52 participants were taken within 1-6 days of them being exposed to the virus. This enabled the researchers to analyse the levels of pre-existing T cells induced by previous common cold coronavirus infections that also cross-recognise proteins of the SARS-CoV-2 virus [1].

The researchers found that there were significantly higher levels of these cross-reactive T cells in the 26 people who did not become infected, compared to the 26 people who did become infected. These T cells targeted internal proteins within the SARS-CoV-2 virus, rather than the spike protein on the surface of the virus, to protect against infection [2].

Current vaccines do not induce an immune response to these internal proteins. The researchers say that – alongside our existing effective spike protein-targeting vaccines – these internal proteins offer a new vaccine target that could provide long-lasting protection because T cell responses persist longer than antibody responses which wane within a few months of vaccination.

Professor Ajit Lalvani, senior author of the study and Director of the NIHR Respiratory Infections Health Protection Research Unit at Imperial, says: “Our study provides the clearest evidence to date that T cells induced by common cold coronaviruses play a protective role against SARS-CoV-2 infection. These T cells provide protection by attacking proteins within the virus, rather than the spike protein on its surface.

“The spike protein is under intense immune pressure from vaccine-induced antibody which drives evolution of vaccine escape mutants. In contrast, the internal proteins targeted by the protective T cells we identified mutate much less. Consequently, they are highly conserved between the various SARS-CoV-2 variants, including omicron. New vaccines that include these conserved, internal proteins would therefore induce broadly protective T cell responses that should protect against current and future SARS-CoV-2 variants.”

The researchers note some limitations to their study, including that, because it is small and 88% of participants were of white European ethnicity, it is not possible for them to model demographic factors.

The study was funded by the NIHR Health Protection Research Unit in Respiratory Infections and the Medical Research Council.

For more information, please contact:
Emily Head (she/her)
Media Manager (Medicine)
Imperial College London
T: +44 (0) 20 7594 6900
E: mailto:e.head21@imperial.ac.uk
Out-of-hours duty media officer: +44 (0) 7803 886 248

Notes to editors:
[1] These included external surface proteins (spike, membrane and envelope proteins) on the surface of the SARS-CoV-2 virus, and internal proteins, including nucleocapsid (which packages the virus’ genetic material) and ORF1 (a part of SARS-CoV-2’s replicative machinery).
[2] The targeted internal proteins of SARS-CoV-2 included nucleocapsid and ORF1 only.

About Imperial College London
Imperial College London is one of the world’s leading universities. The College’s 20,000 students and 8,000 staff are working to solve the biggest challenges in science, medicine, engineering and business.
Imperial is University of the Year 2022 in the Times and Sunday Times Good University Guide. It is the world’s fifth most international university, according to Times Higher Education, with academic ties to more than 150 countries. Reuters named the College as the UK’s most innovative university because of its exceptional entrepreneurial culture and ties to industry.
Imperial staff, students and alumni are working round-the-clock to combat COVID-19. Imperial is at the forefront of coronavirus epidemiology, virology, vaccine development and diagnostics.
http://www.imperial.ac.uk/

About NIHR
The mission of the National Institute for Health Research (NIHR) is to improve the health and wealth of the nation through research. We do this by: – Funding high quality, timely research that benefits the NHS, public health and social care;
– Investing in world-class expertise, facilities and a skilled delivery workforce to translate discoveries into improved treatments and services;
– Partnering with patients, service users, carers and communities, improving the relevance, quality and impact of our research;
– Attracting, training and supporting the best researchers to tackle complex health and social care challenges;
– Collaborating with other public funders, charities and industry to help shape a cohesive and globally competitive research system;
– Funding applied global health research and training to meet the needs of the poorest people in low and middle income countries.
NIHR is funded by the Department of Health and Social Care. Its work in low and middle income countries is principally funded through UK Aid from the UK government.

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Source: T cells from common colds cross-protect against infection with SARS-CoV-2



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