People Who Have ”T Cells’ From Other Coronavirus Infections Are Resistant to COVID-19

Two separate studies indicate

Immune warriors known as T cells help us fight some viruses, but their importance for battling SARS-CoV-2, the virus that causes COVID-19, has been unclear. Now, two studies reveal infected people harbor T cells that target the virus—and may help them recover. Both studies also found some people never infected with SARS-CoV-2 have these cellular defenses, most likely because they were previously infected with other coronaviruses.

“This is encouraging data,” says virologist Angela Rasmussen of Columbia University. Although the studies don’t clarify whether people who clear a SARS-CoV-2 infection can ward off the virus in the future, both identified strong T cell responses to it, which “bodes well for the development of long-term protective immunity,” Rasmussen says. The findings could also help researchers create better vaccines.

The more than 100 COVID-19 vaccines in development mainly focus on another immune response: antibodies. These proteins are made by B cells and ideally latch onto SARS-CoV-2 and prevent it from entering cells. T cells, in contrast, thwart infections in two different ways. Helper T cells spur B cells and other immune defenders into action, whereas killer T cells target and destroy infected cells. The severity of disease can depend on the strength of these T cell responses.

Using bioinformatics tools, a team led by Shane Crotty and Alessandro Sette, immunologists at the La Jolla Institute for Immunology, predicted which viral protein pieces would provoke the most powerful T cell responses. They then exposed immune cells from 10 patients who had recovered from mild cases of COVID-19 to these viral snippets.

All of the patients carried helper T cells that recognized the SARS-CoV-2 spike protein, which enables the virus to infiltrate our cells. They also harbored helper T cells that react to other SARS-CoV-2 proteins. And the team detected virus-specific killer T cells in 70% of the subjects, they report today in Cell. “The immune system sees this virus and mounts an effective immune response,” Sette says.

The results jibe with those of a study posted as a preprint on medRxiv on 22 April by immunologist Andreas Thiel of the Charité University Hospital in Berlin and colleagues. They identified helper T cells targeting the spike protein in 15 out of 18 patients hospitalized with COVID-19.

The teams also asked whether people who haven’t been infected with SARS-CoV-2 also produce cells that combat it. Thiel and colleagues analyzed blood from 68 uninfected people and found that 34% hosted helper T cells that recognized SARS-CoV-2. The La Jolla team detected this crossreactivity in about half of stored blood samples collected between 2015 and 2018, well before the current pandemic began. The researchers think these cells were likely triggered by past infection with one of the four human coronaviruses that cause colds; proteins in these viruses resemble those of SARS-CoV-2.

The results suggest “one reason that a large chunk of the population may be able to deal with the virus is that we may have some small residual immunity from our exposure to common cold viruses,” says viral immunologist Steven Varga of the University of Iowa. However, neither of the studies attempted to establish that people with crossreactivity don’t become as ill from COVID-19.

Before these studies, researchers didn’t know whether T cells played a role in eliminating SARS-CoV-2, or even whether they could provoke a dangerous immune system overreaction. “These papers are really helpful because they start to define the T cell component of the immune response,” Rasmussen says. But she and other scientists caution that the results do not mean that people who have recovered from COVID-19 are protected from reinfection.

To spark production of antibodies, vaccines against the virus need to stimulate helper T cells, Crotty notes. “It is encouraging that we are seeing good helper T cell responses against SARS-CoV-2 in COVID-19 cases,” he says. The results have other significant implications for vaccine design, says molecular virologist Rachel Graham of the University of North Carolina, Chapel Hill. Most vaccines under development aim to elicit an immune response against spike, but the La Jolla group’s study determined that T cells reacted to several viral proteins, suggesting vaccines that sic the immune system on these proteins as well could be more effective. “It is important to not just concentrate on one protein,” Graham says.

Source: Science

  1. Bob avlon says

    Simple Beta Glucan 1-3 1-6 has been shown to strengthen the bodies natural killer T cells against earlier corona viruses. Antibiotics have been given against them also. Quite successfully, no problem. Now neither used. Out of the blue the bought and sold media allow a malaria drug to be promoted. Is it an observation of the obvious world wide program or a strange media hype fear mongering using statistics seemingly out of nowhere.

  2. hoyeru says

    Anti empire is so silly. the West has moved beyond the fake corona virus “pandemic” and are already preparing their new world order that aims to exclude China from the world, while anti-empire is still posting irrelevant and stupid articles about corona virus.

    Get a clue: everyone has T cells and everyone has been exposed to corona viruses at once point in their lives. Corona virus cases the common cold after all.

    1. Rim Shepetys says

      Guess Anti-Empire is attempting to educate the silly majority of people
      who want to stay in prison lockdown, participate in anti-social distancing,
      and wear re-infecting masks.
      So who is silly?
      Most definitely not the writer or the site.

  3. tom greg says

    Interesting. Thanks.

  4. voza0db says

    Since RNA “SARS-CoV-2” is just a mere weak variant of SARS-CoV-1, it’s perfectly acceptable that that is happening…

  5. Bill Rood says

    This study is compatible with the recent interview of Prof. Dolores Cahill. In that interview, Dr. Cahill pointed out that a significant portion of the population is immune to SARS-CoV-2 without ever having been exposed to it, which means that we reach “herd immunity” with a much lower infection rate than people have been assuming.

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