How T-cells in Your Immune System Are Protecting From Covid-19 Infection?

By NATE GARTRELL On Nov 14, 2021

While millions are exposed quickly to the infection, the reason some people test negative despite exposure to Covid-19 has been determined by new research.

A group of researchers at the University College London identified a link between resistance to Coronavirus-19 and T-cells capable of cleaning up SARS-CoV-2 and other coronavirus infections at an early stage, providing hope that a vaccine technology may be developed in the future.

“Everyone has anecdotal evidence of people being exposed but not succumbing to contamination,” explained the paper’s lead author, immunologist Leo Swadling at University College London.

“What we didn’t know is whether these individuals really did manage to completely avoid the virus or whether they naturally cleared the virus before it was detectable by routine tests.”

“Memory T-cells” that trigger an immune response against viruses, have been found to be produced in some people in response to similar infections from other seasonal coronaviruses such as those that cause common colds. These “memory T-cells” prevented some people from contracting Covid-19, according to research published in Nature on Wednesday.

As a result, some people who contracted the virus were able to fight it than many others, and the virus could not stay long enough in their systems to develop antibodies or cause any illness.

Researchers have found a way to make vaccines stronger, and therefore more effective, against Covid-19 by using this technology.

During the first wave of the pandemic, 731 healthcare workers were studied and their immune responses monitored. In spite of high-risk exposure, 58 participants of the study test negative for Covid, despite a spike in T-cells in their samples. These results tell that some participants were already immune even before the outbreak started.

Current Covid-19 vaccines rely on antibodies to fight infection, but these rare T-cells were able to recognize the virus’ inside machinery, allowing them to fight faster.

“T cells, white blood cells that play a central role in our immune system, can ‘sniff out’ coronavirus proteins even when buried within the virus particle, in contrast to antibodies that ‘grab hold’ of shapes on the surface,” University of Reading associate professor Alexander Edwards said.

“This provides hard evidence for what might be expected from virus-host biology — different people can expect different outcomes after being exposed to a virus. Sometimes you may be lucky and not get infected; other times you might be fully infected and experience mild or severe disease,” he explained.

The findings could lead to the development of vaccines that are equipped with T cells to activate the immune system when the body is exposed to a virus before symptoms appear or antibodies are formed.

“A vaccine that primes T-cell immunity against different viral protein targets that are shared between many different coronaviruses would complement our spike vaccines that induce neutralizing antibodies. Because these are components within the virus, antibodies are less effective — instead, T cells come into play,” Edwards said.

“Hopefully this study will lead to further advances in vaccine development, as we need all the types of vaccine we can get.”