Researchers in the United States have conducted a study showing that the coronavirus disease 2019 (COVID-19) vaccines developed by Pfizer-BioNTech and Moderna generate a coordinated adaptive immune response that is capable of eliciting recall responses to future infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
The team from the University of California found that immunization with either Pfizer-BioNTech’s BNT162b2 or Moderna’s mRNA-1273 vaccine-induced enrichment of spike-specific B cells.
The viral spike protein mediates the initial stage of the SARS-CoV-2 infection process and is the primary target of antibodies following natural infection or vaccination.
Ilhem Messaoudi and colleagues say that vaccination also activated CD4 T cells and induced robust antigen-specific polyfunctional CD4 T cell responses.
Furthermore, clonally expanded CD8 T cells were observed in all vaccine recipients.
A pre-print version of the research paper is available on the bioRxiv* server, while the article undergoes peer review.
Vaccination and infection provide two different pathways to immunity
Since the COVID-19 outbreak first began in December 2019 in Wuhan, China, intense global efforts to rapidly develop effective vaccines against the causative agent SARS-CoV-2 have led to the emergency use authorization of several vaccines.
These include the messenger RNA- (mRNA) based vaccines developed by Pfizer (BNT162b2) and Moderna (mRNA-1273). Findings from clinical trials indicated that a 95% maximal protection is achieved within 1 to 2 months following the second dose of either vaccine, including protection against several circulating SARS-CoV-2 variants of concern.
However, the mechanisms by which these vaccines elicit long-lasting cellular immune responses to the virus remain poorly understood.
Natural infection and vaccination provide two different pathways to immunity, which studies have previously shown to be characterized by distinct T and B cell responses.
“Additional studies that integrate functional, transcriptional, and repertoire analysis of the memory immune cell response to COVID-19 mRNA vaccination are needed,” writes Messaoudi and colleagues.
What did the researchers do?
The team used single-cell RNA sequencing and functional assays to assess humoral (antibody) and cellular responses to two doses of either the Pfizer-BioNTech or Moderna mRNA vaccine (14 days following a second dose) in four individuals. The results were compared with the immune responses observed in three convalescent individuals who had experienced asymptomatic or mild infection.
What did the study find?
Both infection and vaccination induced anti-SARS-CoV-2 binding and neutralizing antibodies.
These antibodies were detected as early as two weeks following a first vaccine dose, with levels increasing several-fold after a second dose.
While neutralizing antibody titers following the first vaccine dose were comparable to those among convalescent individuals, significantly higher levels were observed in the vaccinees following the booster dose.
However, several important B cell adaptations were shared between vaccinees and convalescent individuals.
Analysis by flow cytometry revealed a reduction in the level of naïve B cells, but an expansion of memory B cells in both groups.
Additionally, single-cell RNA sequencing showed a reduction in IgA+ memory B cells following vaccination, a finding that has recently been described for convalescent individuals.
News
We May Never Know if AI Is Conscious, Says Cambridge Philosopher
As claims about conscious AI grow louder, a Cambridge philosopher argues that we lack the evidence to know whether machines can truly be conscious, let alone morally significant. A philosopher at the University of [...]
AI Helped Scientists Stop a Virus With One Tiny Change
Using AI, researchers identified one tiny molecular interaction that viruses need to infect cells. Disrupting it stopped the virus before infection could begin. Washington State University scientists have uncovered a method to interfere with a key [...]
Deadly Hospital Fungus May Finally Have a Weakness
A deadly, drug-resistant hospital fungus may finally have a weakness—and scientists think they’ve found it. Researchers have identified a genetic process that could open the door to new treatments for a dangerous fungal infection [...]
Fever-Proof Bird Flu Variant Could Fuel the Next Pandemic
Bird flu viruses present a significant risk to humans because they can continue replicating at temperatures higher than a typical fever. Fever is one of the body’s main tools for slowing or stopping viral [...]
What could the future of nanoscience look like?
Society has a lot to thank for nanoscience. From improved health monitoring to reducing the size of electronics, scientists’ ability to delve deeper and better understand chemistry at the nanoscale has opened up numerous [...]
Scientists Melt Cancer’s Hidden “Power Hubs” and Stop Tumor Growth
Researchers discovered that in a rare kidney cancer, RNA builds droplet-like hubs that act as growth control centers inside tumor cells. By engineering a molecular switch to dissolve these hubs, they were able to halt cancer [...]
Platelet-inspired nanoparticles could improve treatment of inflammatory diseases
Scientists have developed platelet-inspired nanoparticles that deliver anti-inflammatory drugs directly to brain-computer interface implants, doubling their effectiveness. Scientists have found a way to improve the performance of brain-computer interface (BCI) electrodes by delivering anti-inflammatory drugs directly [...]
After 150 years, a new chapter in cancer therapy is finally beginning
For decades, researchers have been looking for ways to destroy cancer cells in a targeted manner without further weakening the body. But for many patients whose immune system is severely impaired by chemotherapy or radiation, [...]
Older chemical libraries show promise for fighting resistant strains of COVID-19 virus
SARS‑CoV‑2, the virus that causes COVID-19, continues to mutate, with some newer strains becoming less responsive to current antiviral treatments like Paxlovid. Now, University of California San Diego scientists and an international team of [...]
Lower doses of immunotherapy for skin cancer give better results, study suggests
According to a new study, lower doses of approved immunotherapy for malignant melanoma can give better results against tumors, while reducing side effects. This is reported by researchers at Karolinska Institutet in the Journal of the National [...]
Researchers highlight five pathways through which microplastics can harm the brain
Microplastics could be fueling neurodegenerative diseases like Alzheimer's and Parkinson's, with a new study highlighting five ways microplastics can trigger inflammation and damage in the brain. More than 57 million people live with dementia, [...]
Tiny Metal Nanodots Obliterate Cancer Cells While Largely Sparing Healthy Tissue
Scientists have developed tiny metal-oxide particles that push cancer cells past their stress limits while sparing healthy tissue. An international team led by RMIT University has developed tiny particles called nanodots, crafted from a metallic compound, [...]
Gold Nanoclusters Could Supercharge Quantum Computers
Researchers found that gold “super atoms” can behave like the atoms in top-tier quantum systems—only far easier to scale. These tiny clusters can be customized at the molecular level, offering a powerful, tunable foundation [...]
A single shot of HPV vaccine may be enough to fight cervical cancer, study finds
WASHINGTON -- A single HPV vaccination appears just as effective as two doses at preventing the viral infection that causes cervical cancer, researchers reported Wednesday. HPV, or human papillomavirus, is very common and spread [...]
New technique overcomes technological barrier in 3D brain imaging
Scientists at the Swiss Light Source SLS have succeeded in mapping a piece of brain tissue in 3D at unprecedented resolution using X-rays, non-destructively. The breakthrough overcomes a long-standing technological barrier that had limited [...]
Scientists Uncover Hidden Blood Pattern in Long COVID
Researchers found persistent microclot and NET structures in Long COVID blood that may explain long-lasting symptoms. Researchers examining Long COVID have identified a structural connection between circulating microclots and neutrophil extracellular traps (NETs). The [...]
