Nobel Prize awardee Shimon Sakaguchi is being lauded for his work on Tregs – learn more about how he’s used mass cytometry in his research.
Study of the immune system is time-consuming and complex. For decades, scientists have grappled with understanding this vast network of organs, proteins and cells that defend the body from disease and infection and promote healing. Regulatory T cells, a subpopulation of T cells that modulate the immune system, have emerged as a new frontier in investigating autoimmune function. Subsequently, Tregs are gaining traction as a pillar of medicine – there are currently more than 200 clinical trials underway involving Tregs, with the aim to treat common diseases, cancer or to improve outcomes following organ transplantation.
Tregs are known for playing a critical role in the immune system. Among other functions, these specialized immune cells create a balanced immune response by maintaining homeostasis; help prevent tumors, allergies and autoimmune disorders; counter inflammation; and even act as gatekeepers to protect the brain. Their role is varied and complex, and many aspects of Treg biology remain obscure. Treg identification is difficult, since biomarkers used in Treg research are thought to represent T cell activation in general as opposed to being Treg-specific.
Researchers only fully characterized Tregs at the start of the 21st century. Before then, scientists doubted whether a distinct “peacekeeper” cell population – cells that prevent the immune system from overreacting and harming the body – even existed. It wasn’t until 1995, when Japanese scientist Shimon Sakaguchi identified the existence of a distinct cell population that served as a brake on the immune system, that the name “regulatory T cells” entered the vernacular. Six years later, scientists Mary Brunkow and Fred Ramsdell identified a gene they named FoxP3 that, when damaged, caused severe autoimmune problems in mice. Just two years after that, Sakaguchi and his team linked their research, proving that the FoxP3 gene governed the development of Tregs. This chain of discovery helped explain how the immune system self-regulates through life by distinguishing between harmful interlopers and healthy cells, which in turn has led to the current swell of Treg clinical trials.
Brunkow, Ramsdell and Sakaguchi were awarded the 2025 Nobel Prize in Physiology or Medicine for their discoveries, which launched the field of peripheral tolerance and spurred the development of medical treatments for cancer and autoimmune disease. The win has catapulted regulatory T cells yet again to the forefront of scientific discussion, with researchers looking to manipulate Tregs to narrow the gap between understanding the immune system and investigating it in a lab.
Sakaguchi, a long-time user of mass cytometry, has used CyTOF™ platforms to analyze Treg function and try to better understand their role in regulating immune homeostasis in health and disease. He’s written several publications that include CyTOF technology in Treg profiling and analysis and has even co-authored a book chapter in Methods in Molecular Biology. Titled Using Mass Cytometry to Address Tfh and Tfr Heterogeneity, the chapter details how to analyze the frequency and phenotype of the populations of T follicular helper cells and T-follicular regulatory cells found in humans by mass cytometry.
Here is some other research from Sakaguchi featuring CyTOF systems:
- In a 2025 Nature Communications article, Sakaguchi and team developed a technique – single-cell suppression profiling of human Tregs (scSPOT) – that used a 52-marker CyTOF panel to try to assess the effect of Tregs on all other cell types simultaneously and gain a more accurate picture of physiologically relevant responses. The team identified cell types using high-dimensional clustering and canonical markers to separate lineages; each lineage was further subclustered into relevant subpopulations, which allowed the researchers to better compare conditions. scSPOT allowed for “fine dissection” of Treg-mediated suppression of all immune cells simultaneously, meaning the team could home in on cells of interest, including CD8 effector memory (EM) cells and plasmablasts. CyTOF technology enabled “an unprecedented level of detail on the suppression status for all immune subsets simultaneously while also providing detailed information on Tregs themselves,” offering a more nuanced understanding of Treg function and its impact on immune homeostasis.
- Sakaguchi and team also published an scSPOT protocol in Bio-Protocol. Mass cytometry is used to quantify cell division and phenotypic responses across multiple immune subsets, allowing for integrated analysis of Treg function with compatibility for patient profiling and drug evaluation.
- In an article published in Science Advances in 2025, researchers looked to clarify the stages of T follicular regulatory (Tfr) cell formation. Tfr cells are a subset of Tregs that specialize in modulating immune responses within germinal centers; by suppressing T follicular helper cells, they help maintain homeostasis of the immune system and prevent autoantibody generation. Sakaguchi and his co-authors used mass cytometry to assess human tonsil tissue, which allowed them to identify a circulating naive-like CD45RA+ Tfr precursor subset (preTfr). The researchers demonstrated that preTfr cells are significantly reduced in the blood of patients with COVID-19 and patients with sepsis, suggesting that Tfr formation is disrupted at an early stage during severe disease and could be key in future therapeutic strategies for inflammatory conditions and autoimmune diseases.
Mass cytometry is the only single-cell technique that can deeply profile a broad range of surface and functional markers simultaneously on the same cell, capturing critical biological insights and providing a more accurate picture of Treg function. CyTOF systems empower researchers to analyze immune responses at a scale not possible with other methods: The scSPOT workflow using a CyTOF panel allowed for “a more comprehensive and nuanced understanding of Treg suppression compared to previous methodologies”; researchers also said that the insights delivered by scSPOT and CyTOF technology “far exceed what traditional methods can offer.”
Learn more about why mass cytometry is such a powerful tool for studying how cells function, how diseases develop, and how new treatments can be made safer and more effective.