SARS-CoV-2: Immune from previous colds?
The risk of contracting the SARS-CoV-2 coronavirus is high for many people. But some seem downright immune. An English research team has now provided the first evidence that some people have T cells that protect once morest corona infection.
Researchers at Imperial College London provide the first tangible evidence that T immune cells, which were formed as part of previous colds, can protect once morest infection with the SARS-CoV-2 coronavirus. The results were recently published in the renowned specialist journal “Nature Communications” presented.
Cross immunity from other human coronaviruses
The SARS-CoV-2 coronavirus and its variants are responsible for the current pandemic. But even before SARS-CoV-2 there were other, largely harmless coronaviruses that cause colds. Previous studies have shown that T cells acquired as part of such common colds also recognize the coronavirus SARS-CoV-2.
The working group at Imperial College London has now shown for the first time that the presence of such T cells from previous colds can prevent infections with the SARS-CoV-2 coronavirus. “Exposure to the SARS-CoV-2 virus does not always lead to an infection, and we really wanted to understand why,” explains study lead author Dr. Rhia Kundu.
No infection despite exposure
As part of the study, the team examined 52 non-vaccinated participants who lived with people who had been infected with SARS-CoV-2. PCR tests were carried out on all subjects at the start of the study and four and seven days later to determine whether they had become infected. In addition, blood was drawn from everyone involved. This made it possible to analyze the number of T cells that were already present, which were caused by previous infections with other human coronaviruses.
It turned out that 26 people did not become infected with SARS-CoV-2 despite living with one infected person. The analysis of the samples shows that these people had a significantly higher level of corona-specific T cells than the participants who were also infected with SARS-CoV-2 in the course of the study.
Cold T cells also protect once morest SARS-CoV-2
“We have found that a high number of pre-existing T cells, which the body produces when infected with other human coronaviruses such as the common cold, can protect once morest COVID-19 infection,” confirms Dr. Kundu.
Just a form of protection
“This is an important discovery, but only one form of protection, and I would like to emphasize that it should not be relied on alone,” says the scientist. The best protection once morest COVID-19 is a full vaccination, including a booster vaccination.
T cells do not target the spike protein
Another important finding emerges from the results. The T cells found were not directed once morest the spike protein of the virus like antibodies, but once morest internal proteins. However, current vaccines do not induce an immune response to these internal proteins. At the same time, the discovery shows a new starting point for making future vaccines more effective and universal.
Vaccination with a long-lasting effect
According to the working group, this would enable vaccines to be developed that “offer long-lasting protection, since the T cell reactions last longer than the antibody reactions, which subside within a few months following vaccination”.
New point of attack to avoid escape mutations
“Our study provides the clearest evidence to date that T cells induced by cold coronaviruses play a protective role once morest SARS-CoV-2 infections,” summarizes the lead author of the study, Professor Ajit Lalvani. According to him, these T cells offer protection by attacking proteins inside the virus and not the spike protein on the virus surface.
“The spike protein is under strong immune pressure from vaccine-induced antibodies that drive the evolution of escape mutants,” explains Lalvani. In contrast, according to the professor, the internal proteins mutate much less. Vaccines and immune reactions that target such internal proteins might therefore protect once morest SARS-CoV-2 for longer and more extensively, including the existing and upcoming variants.
Limitation of the results
The researchers point out that so far only a small group has been examined with regard to T cells. The results have yet to be checked on a larger cohort. (vb)
Author and source information
This text complies with the requirements of specialist medical literature, medical guidelines and current studies and has been checked by medical professionals.
Author:
Diploma-Editor (FH) Volker Blasek
Sources:
- Imperial College London: T cells from common colds cross-protect once morest infection with SARS-CoV-2 (veröffentlicht: 10.01.2022), imperial.ac.uk
- Kundu, R., Narean, J.S., Wang, L. et al.: Cross-reactive memory T cells associate with protection once morest SARS-CoV-2 infection in COVID-19 contacts; in: Nature Communications, 2022., nature.com
Important NOTE:
This article is for general guidance only and is not intended to be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor.
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