Cell: What makes mRNA vaccines effective against SARS-CoV-2

The first two vaccines developed using mRNA vaccine technology—Pfizer/BioNTech and Moderna COVID-19 vaccine—are arguably the two most effective COVID-19 vaccines developed so far
.

In clinical trials, these two vaccines are more than 90% effective in preventing symptomatic infections, easily surpassing the US Food and Drug Administration (Food and Drug Administration, referred to as fda) for considering emergency use of the COVID-19 vaccine.

Although breakthrough infections have increased with the emergence of delta and omicron variants, the vaccine is still quite effective in preventing hospitalization and death
.

The success of this new technology has prompted scientists to try to figure out why messenger RNA vaccines are so effective, and whether the protection they provide may last as new mutations emerge

A new study by researchers at Washington University St.
Louis School of Medicine and St.
Jude Children’s Research Hospital reveals the quality of the immune response triggered by the mRNA vaccine
.

Studies have shown that Pfizer’s vaccine strongly and continuously activates a kind of auxiliary immune cells that help antibody-producing cells to produce a large number of increasingly stronger antibodies and promote the development of certain immune memories

In addition, many T follicular helper cells are activated by a part of the virus, and even in the highly mutated omicron variant, part of the virus does not seem to be mutated
.

The results of the study, published online in the journal Cell on December 22, 2021, help explain why Pfizer’s vaccine can produce such high levels of neutralizing antibodies and show that even if the virus changes, vaccination can help many People continue to produce potent antibodies

"The longer the T follicle helper cells provide help, the better the antibody, and the more likely you are to have a good memory response," said Philip Mudd, MD, assistant professor of emergency medicine at the University of Washington and co-corresponding author.

.

"In this study, we found that the response of these T follicle helper cells has been ongoing

The first antibodies produced after infection or vaccination are often not very good
.

B cells need to be trained by the lymph node germinal center to produce truly powerful antibodies

Earlier this year, Dr.
Ali Ellebedy, associate professor of pathology and immunology, medicine and molecular microbiology at the University of Washington, reported that nearly 4 months after people received the first dose of Pfizer vaccine, they still have germinal centers in their lymph nodes.
The center is mass-producing immune cells against SARS-CoV-2 that causes COVID-19
.

In this latest study, Mudd and co-corresponding author Ellebedy and Dr.
Paul Thomas of St.
Jude aimed to understand the role of T follicle helper cells in generating such a strong reproductive center response
.

The research team also includes co-first authors Dr.

The researchers recruited 15 volunteers, and each volunteer received two doses of Pfizer vaccine, three weeks apart
.

21 days after the first injection, that is, before the second injection, the volunteers underwent surgery to extract the germinal center from the lymph nodes; 28 days, 35 days, 60 days, 110 days, 200 days

Researchers are now studying what happens when the dose is increased, and whether changes in T follicle helper cells can explain why people with compromised immune systems, such as those infected with HIV, do not develop a strong antibody response
.

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Magazine

cell

DOI

j.
cell.
2021.
12.
026

Methodological research

Observational research

Subject of research

people

Article title

SARS-CoV-2 mRNA vaccination can trigger a strong and long-lasting T follicular helper cell response in humans
.

Article publication date

22nd-December-2021

COI statement

The funding received by the Ellebedy laboratory under the sponsored research agreement has nothing to do with the data provided by Emergent BioSolutions and AbbVie in the current study
.
AHE has received consulting fees from Mubadala Investment Company, InBios International LLC and Fimbrion Therapeutics, and is the founder of ImmuneBio Consulting LLC
.
PGT has consulted and/or received honoraria and travel support from Illumina, Johnson & Johnson, and 10X Genome
.
pgt is a member of the scientific advisory board of immune scape and Cytoagents
.
The author has applied for patents on certain aspects of these studies
.