A study reveals the mystery of some people receiving a negative...

A new study conducted by University College London confirmed that people who get a negative result in the Corona virus test despite exposure to the virus may have an “immune memory”, and researchers said that some individuals get rid of the virus quickly due to the strong immune response from the virus. T cells in the body, which means that the tests record negative results.

And according to what the British newspaper “The Guardian” reported, scientists said that a proportion of people suffer from a “failed infection” in which the virus enters the body, but is cleared by T cells in the immune system at an early stage, which means that PCR tests (PCR) and the antibodies register a negative result.

The scientists said the discovery could pave the way for a new generation of vaccines that target the T-cell response, which can produce longer-lasting immunity.

“Everyone had anecdotal evidence of infection but did not succumb to the virus,” said Leo Swadling, an immunologist at University College London and lead author of the study. “What we didn’t know was whether these individuals really managed to avoid the virus completely or whether They had cleared the virus naturally before it was detected by routine tests.”

The study closely monitored health care workers for signs of infection and immune responses during the first wave of the epidemic.

Despite the high exposure risk, 58 participants never tested positive for COVID-19.

However, blood samples taken from these people showed that they had an increase in T cells that reacted against corona, compared to samples taken before the outbreak of the epidemic and compared to people who were not exposed to the virus at all also had increases in another blood marker for viral infection.

The study indicated that a subset of people already had a T-cell memory of a previous infection from other seasonal coronaviruses that cause the common cold, which protects them from the Corona virus.

These immune cells “sniff out” proteins in the coronavirus’ replication machinery and these proteins are in common with seasonal coronaviruses – and in some people this response was fast and effective enough to clear the infection at an early stage.

“These pre-existing T cells are ready to recognize corona,” Swadling said.

Alexander Edwards, associate professor of biomedical technology at the University of Reading, said: “This study identifies a new finding – that exposure to viruses is sufficient to activate part of your immune system but not enough to experience symptoms, detect significant levels of virus or escalate an antibody response.”

“This finding is particularly important because immune response T cells tend to confer longer-lasting immunity, usually for years rather than months, than antibodies,” he added.

Almost all existing corona vaccines focus on preparing antibodies against the vital spike protein that helps corona enter cells.

These neutralizing antibodies provide excellent protection against severe complications. However, immunity wanes over time, and another potential weakness of spike protein-based vaccines is that this region of the virus is known to mutate.

By contrast, the T-cell response does not tend to fade as quickly, and the intrinsic transcription mechanism that it targets is highly conserved across coronaviruses, meaning that a vaccine that targets this region as well would likely protect against new strains—and perhaps even against strains. completely new.