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
Lipid nanoparticles carry gene-editing cancer drugs past tumor defenses
As they grow, solid tumors surround themselves with a thick, hard-to-penetrate wall of molecular defenses. Getting drugs past that barricade is notoriously difficult. Now, scientists at UT Southwestern have developed nanoparticles that can break [...]
Graphene Nanosensor Detects Biomarkers Through Tears
In an article recently published in the journal Talanta, researchers demonstrated a new approach to enable the specific detection of biomarkers in human tear by employing an aptamer-based graphene affinity nanosensor. The ability to detect [...]
How Nanotechnology Can Make a Splash in Aquaculture
Selenium (Se) is an essential element found in aquatic feeds that promotes the proper development, wellbeing, and fitness of marine animals. Selenium can be transformed into nanomaterials that are more easily accessible, absorbed, and consumed by [...]
Super-Resolution Imaging Method For Multiple Fluorescence Microscopy Applications
In an article recently published in the journal Nanotechnology, researchers employed a single particle imaging method for fluorescence excitation with moderate intensity to achieve spatial resolution. Here, the semiconductor nanocrystals were accessed, whose emission lifetimes [...]
Trials to begin on new SA COVID-19 vaccine
A new COVID-19 vaccine developed in South Australia and administered with a needle-free device is to begin human trials. Designed by University of Adelaide researchers the DNA vaccine also targets the Omicron variant of [...]
Towards Carbon Clean Manufacturing with Eco-Friendly Nano-Lubricants
Grinding is an essential manufacturing process, yet the heat due to friction associated with the process causes damage to the part being processed. Lubrication is used to reduce friction; however, traditional petroleum-based lubricants can [...]
Researchers develop hybrid sensor that could help diagnose cancer
A team of researchers from HSE University, Skoltech, MPGU, and MISIS have developed a nanophotonic-microfluidic sensor whose potential applications include cancer detection, monitoring and treatment response assessment. Today, the device can identify gases and [...]
Scientists Develop ‘Nanomachines’ That Can Penetrate And Kill Cancer Cells
Researchers have made a scientific breakthrough with the development of ‘nanomachines’ that can kill cancerous cells. The research team headed by Dr Youngdo Jeong from the Center for Advanced Biomolecular Recognition at the Korea Institute of Science and Technology (KIST) has engineered [...]
Green Method to Make Nanoparticles and Ultrafine Powder
A novel freeze-dissolving approach has been devised that offers greater efficiency and sustainability compared to the classic freeze-drying process to make superfine powder or nanoparticles. In the research published in the journal ACS Sustainable Chemistry & Engineering, sphere-shaped [...]
Participants wanted for study on the regulation of what future AI-driven nanomedicines should look like
Would you like to help in some research on the regulation of what future AI-driven nanomedicines should look like? If so, researchers at the University of Bristol are looking for volunteers to discuss ethical [...]
Could gold nanoparticles help treat cancer?
Gold nanoparticles are minuscule particles made of gold. From drug and gene delivery to photothermal and photodynamic therapies to screening and diagnostic tests to radiation therapy, X-ray imaging and CT scans, these small particles [...]
Carbon Dots Target Nucleolus and Monitor in Real-Time
In an article recently published in the journal Applied Surface Science, the researchers synthesized green fluorescent carbon dots (G-CDs) from 3,5-diaminobenzoic acid and citric acid. The as-prepared G-CDs were used to target the nucleolus and [...]
Green Nanoformulation for Anti-Cancer and Antibacterial Functions
Doxorubicin (DOX) is a powerful anti-cancer medication, and efforts have been made to design nanostructures for delivering it to cancerous cells. The nanostructures increase the cytotoxic effects of DOX on cancerous cells, while reducing the negative effects [...]
New drug delivery system releases therapeutic cargo only when bacteria are present
A team of Brown University researchers has developed a new responsive material that is able to release encapsulated cargo only when pathogenic bacteria are present. The material could be used to make wound dressings [...]
Hairy Cell Leukemia Complicated by Severe COVID-19: A Case Study
Novel three-drug regimen used to manage life-threatening developments. In April 2021, a 42-year-old man reached out to Brian Hill, MD, PhD, for a second opinion after being diagnosed with hairy cell leukemia following a bone [...]
We’re now in the ‘age of pandemics’. Can we stop the next one?
When the virus hunters landed in the remote African village of Yambuku in 1976, the nuns warned them to stay back. The sisters had cordoned off the area where they were caring for people [...]