Omicron, the new variant of the SARS-CoV-2 virus, has taken the world by storm, forcing countries to reintroduce restrictions and bans. The variant does not even spare vaccinated or Covid sufferers and brings their mutations and the reaction of the human body to them into conversation.
A new study suggests that T cells in the human body target the coronavirus and last for a long time.
“Well-preserved T-cell immunity to Omicron will likely help protect against severe Covid-19,” supports the initial guess of South African doctors when most patients with Omicron infections did not become seriously ill, the research says. Here’s what the study says.
How does the immune system work?
The immune system protects us from various infectious diseases caused by bacteria, viruses, fungi or parasites. To do this, it first determines what type of infectious agent or pathogen is causing the infection, after which it triggers an appropriate response. It is crucial that it simultaneously produces memory cells that can recognize the same pathogen in the future. This makes the immune system fit to fight possible reinfections.
What role do T cells play?
When the immune system determines that an antiviral response is needed, it starts a combination of two types of immunity. One is mediated by antibodies and the other is mediated by T cells or cell mediated. The antibodies bind to viruses and neutralize them so that they do not infect cells. Meanwhile, T cells kill cells that have already been infected with the virus.
While both types of immunity are important in fighting viruses, cell-mediated immunity is far more effective and long-lasting in eradicating viruses. This is important in the ongoing fight against Covid-19.
What science supports the role of T cells against Covid-19?
Research has already shown that cell-mediated immunity is a powerful weapon against human coronaviruses, of which SARS-CoV-2 belongs to the family. A 2016 study showed that T-cell immunity to the SARS coronavirus lasted for up to 11 years. It offers complete, effective and permanent protection against SARS.
A Dutch study of 10 patients with severe Covid-19 found that by the time they were admitted to the intensive care unit, most of them already had T cells that recognized and targeted the coronavirus. The results may provide information about the role of T cells in fighting the disease and help develop vaccines that stimulate the body to produce these cells.
The study, led by Alessandro Sette from the La Jolla Institute for Immunology in California and Rory de Vries from the Erasmus MC in Rotterdam, found that patients’ T cell levels generally increased over time along with the antibodies that the virus could neutralize, while viral loads decreased. In addition, two uninfected volunteers also had T cells that recognized the virus and responded to it in test tubes, adding to evidence that T cells the body produced in response to previous cold coronavirus infections also responded to it new virus can respond.
In another study, researchers in South Africa exposed copies of the virus to T cells from volunteers who had received vaccines from Johnson & Johnson or Pfizer / BioNTech or who had not been vaccinated, but who had been infected with a previous infection, exposed their own T cells developed version of the coronavirus.
“Despite Omicron’s extensive mutations and reduced susceptibility to neutralizing antibodies, the majority of T-cell responses triggered by vaccines or natural infections recognize the variant,” researchers reported on medRxiv on Tuesday.
(With agency entries)
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