- Some people are less susceptible to SARS-CoV-2 infection.
- A new study suggests that T cells from previous infection with other coronaviruses, such as the common cold, may protect against SARS-CoV-2.
- These T cells target the internal proteins of SARS-CoV-2.
- Vaccines that stimulate T cells are likely to provide longer-lasting protection against SARS-CoV-2 and protect against new variants.
One of the mysteries of COVID-19 is why some people appear resistant to infection despite exposure to SARS-CoV-2. Scientists from Imperial College London have published a
When you catch a cold, your immune system produces antibodies and T cells. These T cells (also called memory T cells) persist much longer than antibodies and help prevent a person from catching the same cold again.
Coronavirus causes around
The observational study, published in
The study took place before any COVID-19 vaccine was approved.
Half of the participants later tested positive for SARS-CoV-2. The other 26 did not contract the virus.
The researchers noted no difference between the two groups. Dr Rhia Kundu of Imperial’s National Heart & Lung Institute and first author of the study, spoke to Medical News Today. She said: ‘We looked at age, biological sex and BMI, and there was no difference between our household contacts who were PCR positive and those who remained PCR negative. […]
“Basically, we also looked at the relationship to the index case (i.e. were they partners, child and parent, or roommate where limited exposure would have occurred) and observed no difference between PCR+ and PCR- contacts. This suggests that exposure was similar between the two groups.
All participants gave blood samples between days 1 and 6 of the study. Scientists analyzed these blood samples for levels of T cells from previous coronavirus infections.
Scientists found that those who did not contract SARS-CoV-2 had significantly higher levels of
Talk to DTM, Dr Arturo Casadevall, Bloomberg Professor Emeritus and Chair of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, commented: “The study is small, but the results are interesting and consistent with other studies. other data that previous experience with other coronavirus infections may affect a person’s susceptibility to COVID-19.
He added: “This study reinforces the notion that an individual’s immunological history, and in particular previous infection with other coronaviruses, is a major factor in determining who becomes ill.”
Current vaccines target spike proteins (antigens) on SARS-CoV-2 and stimulate the production of spike protein-specific antibodies. Cross-reacting T cells target internal proteins of the virus.
Spike antigens on the surface of the virus frequently mutate, giving rise to new variants. The researchers suggest that second-generation vaccines should include spikeless antigen vaccines, as well as spiked antigens. A vaccine that stimulates the production of T cells is likely to confer longer-lasting immunity than a vaccine that only stimulates the production of antibodies.
“By developing vaccines that target the parts of the virus that it cannot so easily change (its internal machinery that it has to replicate), we could better protect an individual’s immune system against emerging variants. The AT cell vaccine could represent this next step in the vaccination strategy to control SARS-CoV-2. »
–Dr. Rhia Kundu.
Dr Casadevall supported his view: “It may be possible to make very different types of vaccines from those we currently use to protect against COVID-19 by prompting
The Imperial research team is now collaborating with other research groups to develop and test second-generation vaccines.
Dr Simon Clarke, associate professor of cellular microbiology at the University of Reading in the UK, told the Science Media Center: ‘It could be a big mistake to think that anyone who has recently had a cold is protected against Covid -19, because coronaviruses represent only 10 to 15% of colds.
Dr. Kundu reiterated this message: “Having had a cold does not necessarily mean that you have these T cells, and vaccination remains the best possible protection against infection and the spread of SARS-CoV-2.
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