A new study confirms the role of vaccine-induced or contagion-induced immunological memory when antibodies fail. But it alone doesn’t stop the infection
A University of Melbourne study conducted in collaboration with the Hong Kong University of Science and Technology and published on Viruses found that the T cells, one of the main defenses against Covid-19, should be effective at creating an immune response against Omicron
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The crucial role of T lymphocytes
The new variant has more mutations than the other variants that emerged earlier, and that means it can escape the antibodies produced by vaccination or infection. But if the virus enters the body, the T lymphocytes will be activated, white blood cells responsible for immunological memory that originate from the marrow. Precisely T cells, also generated by vaccinations and Covid-19 infections, have proven to be fundamental in limiting progression to a serious disease eliminating virus-infected cells.
The other studies
The preliminary study and joins the other five published in the last week, as the scientist reports Eric Topol on twitter: In just a week, six new studies have shown that T cells induced by the vaccine or by previous infections resist quite well against Omicron (ie show cross-reactivity), which should help in the protection of severe disease.
In just a week, 6 new studies have now reported how T cells, induced from multiple vaccines or prior Covid, hold up quite well vs Omicron (ie they exhibit cross-reactivity), which should help protect vs severe disease pic.twitter.com/lWVKlxLMjP
– Eric Topol (@EricTopol) January 3, 2022
How the research was conducted
The Australian team has studied further 1500 fragments of SARS CoV-2 viral proteins, called epitopes, which have been recognized by the T cells of patients recovered from Covid-19 or vaccinated. The results suggest that Omicron is unlikely to be able to evade T cells, adding a new piece to a growing body of evidence coming from research groups around the world that are also studying T-cell responses to Covid-19.
Although Omicron, or some other variant, can potentially escape antibodies, one can still expect one robust T-cell response offer protection and help prevent significant diseases, he said Matthew McKay from the University of Melbourne and co-author of the research. Despite being a preliminary study – he added – we believe that this is positive news.
The details
The study found that by analyzing the viral epitopes of the spike protein that are targeted by T cells, only 20% showed mutations associated with Omicron and even then it does not necessarily mean that the virus will be able to evade T cells. Our further analysis found that more than half of Omicron mutated epitopes are still visible to T cells. This further reduces the possibility that Omicron could escape T cell defenses, the authors write. Based on our data, we predict that T cell responses elicited by vaccines and boosters will continue to protect against Omicron, as observed for other variants.
What does it mean in concrete terms
What do these discoveries mean in concrete terms? The authors warn that theand T cell responses alone do not block infection (and therefore do not prevent transmission) and this would explain the fact that many infections are occurring despite the majority of the population having finished the vaccination cycle. However immunity of T cells, which come into play as a second line of defense, offers a good hope of protection against serious diseases, even when antibodies, which instead represent the first defense, are few or ineffective.
January 5, 2022 (change January 5, 2022 | 10:10)
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