Data from dozens of British medical staff show an attractive possibility: some people can quickly remove the newborn sars-cov-2 infection from their bodies, so that they have never detected the virus positive or even produced antibodies against the virus. The data also suggest that this resistance is produced by immune cells called memory T cells, which may be produced after exposure to the coronavirus that causes the common cold.
Shane Crotty, an immunologist at the La Jola Institute of immunology in California who was not involved in the study, said: “I’ve never seen anything like this. It’s amazing that T cells can control infection so quickly.”.
But the authors of the study strongly warned that their findings did not show that patients with common cold could resist COVID-19 -19. The authors also admit that their findings have many warnings, which means that it is too early to assert that people can prevent infection in the process of infection.
In the study, published in the journal Nature on November 10, the authors examined blood samples taken from nearly 60 British medical staff in the weeks before the pandemic. All of them work in hospitals, which puts them at high risk of infection with COVID-19 -19, but never detected any positive or produced any virus antibodies within four months after the study.
The researchers noted that 20 of these “seronegative” participants had T cell proliferation, suggesting that the immune system may be preparing to resist infection. The level of immune system protein ifi27 also increased in 19 of them, which may be an early marker of sars-cov-2 infection, the authors said. The authors say that these data are evidence of “abortion infection”, which means that the virus has invaded the human body, but it has not been caught.
The authors hypothesized that T cells prevent sars-cov-2 by inactivating a group of viral proteins called replication transcription complexes, which contributes to virus replication. They found evidence supporting this theory: in seronegative subjects, the proportion of T cells recognizing this compound was much higher than that of COVID-19 infected -19 nurses.
The researchers also found that even T cells in blood samples collected before the pandemic can recognize sars-cov-2 and can best recognize replication complexes. The authors say that these T cells may be produced by the coronavirus infection that causes the common cold, but there is no direct evidence of how or when these cells are produced, and other triggers may contribute to their formation.
Most of the existing COVID-19 -19 vaccines target the SARS-CoV-2 spike protein, which is used to invade human cells. Spike proteins vary greatly among different coronaviruses. However, in many types of coronaviruses, the replication complex is similar, which makes this part of the virus a promising target for the “Pan coronavirus” vaccine, which can protect people from a wide range of such viruses, the authors conclude.
However, scientists who did not participate in the study pointed out that there was no conclusive evidence that the medical staff who claimed to have cleared the sars-cov-2 virus actually had sars-cov-2 particles in their bodies from the beginning. This makes it difficult to draw any conclusions about the role of these T cells, said Donna Farber, an immunologist at Columbia University in New York.
Mara meney, a viral immunologist at University College London and co-author of the study, admitted that her team lacked direct confirmation of abortion infection among study participants. But she points out that the timing of the uncontrolled early spread of the virus in the UK is well documented. Therefore, she said, it may not be a coincidence that the researchers found more T cells in the subjects’ blood while visiting British hospitals. “The timing is very clear,” she said.
Clearance for all?
Markus buggett, an immunologist at the Karolinska Institute in Solna, Sweden, said that even if some research participants cleared the sars-cov-2 virus before the epidemic, it is possible that mutant infections such as delta cannot be cleared in the same way. He pointed out that the study only recorded this phenomenon among medical staff, which increases the possibility that only hospital staff and other people who are often exposed to various respiratory viruses can make abortion response.
Nor is this study to determine whether the abortion response is driven by T cells or other unknown immune processes. Crotti said it is important to test T cell theory in animals. Meney said that in a human challenge experiment, participants were deliberately exposed to sars-cov-2, which will help to determine whether these T cells really help clear the infection.
Source from This article is reproduced with permission and was first published on November 11 2021.