COVID-19 patients who experience cytokine storms may make few memory B cells

19-Aug-2020 10:50 AM EDT, by Cell Press

Newswise — The release of massive amounts of proteins called cytokines can lead to some of the most severe symptoms of COVID-19. When large numbers of immune cells release cytokines, this increases inflammation and creates a feedback loop in which more immune cells are activated and this is sometimes called a cytokine storm. An August 19 study in the journal Cell now suggests that high levels of some cytokines may also prevent people who are infected from developing long-term immunity as affected patients were observed to make very few of the type of B cells needed to develop a durable immune response.

"We've seen a lot of studies suggesting that immunity to COVID-19 is not durable because the antibodies decline over time," says co-senior author Shiv Pillai, a professor at Harvard Medical School and member of the Ragon Institute of Massachusetts General Hospital, MIT, and Harvard. "This study provides a mechanism that explains this lower-quality immune response."

The investigators focused on germinal centers--the areas within the lymph nodes and spleens where B cells, the immune cells that produce antibodies, differentiate. Differentiation and changes in antibody genes are required to build immunity to an infectious agent.

"When we looked at the lymph nodes and spleens of patients who died from COVID-19, including some who died very soon after getting the disease, we saw that these germinal center structures had not formed," says co-senior author Robert Padera, a pathology professor at Harvard. "We decided to determine why that's the case."

Because the disease was so new, animal models for studying COVID-19 infection were not yet available at the time they began their study. The researchers instead gained insights from previous studies involving mouse models of other infections that induce cytokine storm syndrome--a malaria model and one of bacterial infection in which germinal centers were lost.

In people with severe COVID-19, one of most abundant cytokines released is called TNF. In the infected mice, TNF appeared to block the formation of germinal centers. In previous cytokine storm models, when the mice were given antibodies to block TNF or had their TNF gene deleted, the germinal centers were able to form. When the researchers studied the lymph nodes of patients who had died of the disease, they found high levels of TNF in these organs. This led them to conclude that TNF may be preventing the germinal centers from forming in people with COVID-19 as well.

"Studies have suggested this lack of germinal centers happens with SARS infections," Pillai says. "We even think this phenomenon occurs in some patients with Ebola, so it was not surprising to us."

The researchers also studied blood and lymphoid tissue from people with active infections who were in different stages of COVID-19. They found that although germinal centers were not formed, B cells were still activated and appeared in the blood, which would allow the patients to produce some neutralizing antibodies. "There is an immune response," Padera says. "It's just not coming from a germinal center."

"Without the germinal centers, there is no long-term memory to the antigens," Pillai adds. He notes that studies of other coronaviruses that cause colds have suggested that someone can get infected with the same coronavirus three or four times in the same year.

The authors say despite their findings, they still believe a successful COVID-19 vaccine can be developed as it should not cause high levels of cytokines to be released.

###

This work was supported by the National Institutes of Health and the National Institute of General Medical Sciences. Funding for these studies from the Massachusetts Consortium of Pathogen Readiness, the Mark and Lisa Schwartz Foundation and Enid Schwartz is also acknowledged.

Cell, Kaneko, Kuo, Boucau, Farmer et al.: "The loss of Bcl-6 expressing T follicular helper cells and the absence of germinal centers in COVID-19" https://www.cell.com/cell/fulltext/S0092-8674(20)31067-9

Cell (@CellCellPress), the flagship journal of Cell Press, is a bimonthly journal that publishes findings of unusual significance in any area of experimental biology, including but not limited to cell biology, molecular biology, neuroscience, immunology, virology and microbiology, cancer, human genetics, systems biology, signaling, and disease mechanisms and therapeutics. Visit: http://www.cell.com/cell. To receive Cell Press media alerts, contact [email protected].

SEE ORIGINAL STUDY




Filters close

Showing results

110 of 5402
Newswise: Palisades Medical Center COVID-19 Vaccine Efforts Support Community Health
Released: 14-Apr-2021 4:20 PM EDT
Palisades Medical Center COVID-19 Vaccine Efforts Support Community Health
Hackensack Meridian Health

Radames and Ana Arocho were all smiles when they arrived on the white school bus, and their enthusiasm was contagious.

Released: 14-Apr-2021 3:10 PM EDT
Most young people eager for COVID-19 vaccine, poll shows
Michigan Medicine - University of Michigan

As older teens and young adults become eligible for COVID-19 vaccination across the country, and younger teens await their turn, new survey data suggest a strong readiness that has grown since fall. But just as with older generations, a shrinking but still sizable minority of people age 14 to 24 say they’re not willing to get vaccinated, or that their decision will depend on safety.

Newswise: 261790_web.jpg
Released: 14-Apr-2021 12:10 PM EDT
A novel, quick, and easy system for genetic analysis of SARS-CoV-2
Osaka University

SARS-CoV-2 is the virus responsible for the COVID-19 pandemic.

Newswise: COVID-19 Mortality Rates in Los Angeles County Higher in Communities with Poor Air Quality
Released: 14-Apr-2021 12:05 PM EDT
COVID-19 Mortality Rates in Los Angeles County Higher in Communities with Poor Air Quality
UCLA Fielding School of Public Health

A research project led by the UCLA Fielding School of Public Health has found that Los Angeles County neighborhoods with poor air quality had the highest death rates from the pandemic.

Released: 14-Apr-2021 10:05 AM EDT
Grant accelerates McMaster University, SQI Diagnostics effort to move infection testing innovation from lab to market
McMaster University

A new grant is helping McMaster University engineers and a Toronto precision-medicine diagnostics company to get infection-testing technology to market while generating opportunities for students.

Newswise: Suppression of COVID-19 Waves Reflects Time-Dependent Social Activity, Not Herd Immunity
Released: 14-Apr-2021 10:05 AM EDT
Suppression of COVID-19 Waves Reflects Time-Dependent Social Activity, Not Herd Immunity
Brookhaven National Laboratory

Scientists developed a new mathematical model for predicting how COVID-19 spreads, accounting for individuals’ varying biological susceptibility and levels of social activity, which naturally change over time.

14-Apr-2021 9:00 AM EDT
Lower COVID-19 rates seen in US states with higher adherence to mask wearing
PLOS

New evidence supports mask wearing in public as key to reducing spread of COVID-19

Newswise: So You Got Vaccinated Against COVID-19. Now What?
Released: 14-Apr-2021 8:05 AM EDT
So You Got Vaccinated Against COVID-19. Now What?
Michigan Medicine - University of Michigan

A slightly lighthearted guide to post-vaccination life, including how to help others who haven't gotten vaccinated yet.


Showing results

110 of 5402

close
1.04612