Just before the pandemic took center stage in 2020, scientists at a T cell memory conference convened to discuss a less than traditional topic: nomenclature. Prior to the event, the workshop organizers sent out a survey with questions related to defining various T cell types. The answers from almost 150 respondents demonstrated a diversity in ideas of how to describe T cells.
These participants shared their opinions and ideas at the nomenclature workshop. At the end of the meeting, the researchers hadn’t made any concrete resolutions, but many felt the impetus for change.
As COVID-19 became a reality, many of these researchers continued their conversations from that final in-person meeting. In November 2025, the group of T cell biologists spanning institutions and continents published a consensus statement in Nature Reviews Immunology that outlined three potential solutions to improve communications surrounding these diverse lymphocytes.1
The Trouble with T Cell Nomenclature
Shortly after scientists first discovered T cells in the 1960s, they identified subtypes based on the cells’ expression of surface markers.2,3 As technologies for characterizing cells advanced, researchers identified more properties of T cells—based on both on their membrane proteins and by the cytokines they produced—and eventually created categorical T cell subtypes.4-7
These categories, though, often failed to distinguish properties like migration ability, differentiation potential, longevity, and antigen persistence. Additionally, the current nomenclature of T cells treats each subtype as a homogenous population of cells, when in fact, many of the characteristics are not always co-regulated.
Pieter Meysman works with experimental researchers to help them analyze T cell data from various sequencing methodologies.
Pieter Meysman
“One of the things that has been kind of an unexpected finding in that regard is that there is this bigger heterogeneity in cells,” said Pieter Meysman, a computational immunologist at the University of Antwerp who was not involved with the consensus statement nor participated in the initial meeting.
This realization introduced further complications into current T cell annotations. David Masopust, a T cell biologist at the University of Minnesota and coauthor on the consensus statement, said in a webinar hosted by the journal that the ability to parse T cells into increasingly defined subsets “has led to an ad hoc, unorganized proliferation of names, and there hasn’t been an effort for a top-down reorganization.”
As a result, many researchers find themselves boxed into naming schemas that may not perfectly describe the cells that they are studying. Conversely, some scientists define subtypes differently. “For me, the most problematic thing is that we had so many different parallel definitions for the same terms,” said Carmen Gerlach, a T cell immunologist at the Karolinska Institute, the University of Regensburg, and the Leibniz Institute for Immunotherapy in the webinar. Gerlach was a panelist at the original nomenclature workshop and a statement coauthor.
Altogether, these limitations in the existing T cell nomenclature complicate communication with researchers in other fields, students, and even fellow immunologists. “We are on a trajectory where the status quo is not going to get better. It is going to get worse with the existing nomenclature,” Masopust said.
Guidelines to Improve Talk About T Cells
To address this growing problem, Masopust, Gerlach, and 62 other T cell researchers developed a consensus statement that takes the first step in updating how scientists talk about T cells. The guideline outlines three possible strategies forward: including an explanation of how a T cell subtype is defined in all publications, conforming to a set definition for existing subtypes, and transitioning to a modular style of T cell naming.
David Masopust co-led a workshop on T cell nomenclature at a meeting with other T cell biologists. The resulting conversations led to a consensus statement with recommendations for naming these cells.
University of Minnesota
“What was put together represents a consensus document. It doesn’t represent an individual’s unique vision of perfection because there were many different competing visions of perfection,” Masopust said.
Meysman said that he thinks the recommendations are an overall positive step for the field of T cell biology. He expects that the first guideline—to include descriptions of how researchers define T cell populations in their studies—will have most researchers’ support. “This is a really important thing going forward in the field, especially with regards to reproducibility,” he said.
Indeed, in a follow-up survey, the authors found that all the respondents agreed that including clear definitions of T cell subtypes in research publications is a good idea. Almost 90 percent also supported a modular nomenclature.
The modular structure that the authors outlined in their consensus statement includes preexisting characteristics and introduces the ability to indicate properties such as migration status. Importantly, researchers can use these properties independently from one another to describe their cells. Masopust explained that the ability to individually characterize T cells gives researchers more flexibility in how they refer to the populations that they are studying.
“This is something that definitely needed to be resolved,” Meysman said about the proposed modular nomenclature. However, regarding the definitions that the authors proposed for unifying existing categorical T cell names, Meysman pointed out that the definitions were largely influenced by mouse data, owing to more research being done on these models. “This is a bit problematic for me because I'm a researcher that purely focuses on human data currently,” he said. “We now have suddenly a lot of categories being defined that we know exist in mice, but we're not even sure exist in humans.”
Challenges to Changing T Cell Nomenclature
While the authors overall view the proposal as a step forward for talking about T cells, they acknowledged that it introduces challenges as well. One is that they proposed several new abbreviations for researchers to learn. They also recognize that the proposed system still fails to strictly indicate some T cell properties, such as organ location.
Carmen Gerlach was a panelist at the T cell nomenclature workshop at the 2020 T cell meeting.
Leibniz Institute for Immunotherapy
Yet, most of the authors have high hopes for their field. “People will recognize this is a movement to simplification not complexification,” Masopust said. In agreement, Gerlach said, “We’ve had a bunch of these changes, and indeed, you just need to get used to them. And most of the time, these changes have been good in the end.”
Highlighting the diversity of opinions within the consensus group, though, another researcher, Rafi Ahmed, an immunologist at Emory University and a statement coauthor, said in the webinar that whereas previous changes in nomenclature updated naming schemes of specific molecules, the present proposal addresses more complex biology. His concern was that the transition to the modular nomenclature could lead to accidentally losing some of this characterization. To minimize this, Ahmed said that it should be acceptable to use both descriptions, with the most important change being to include detailed definitions of how the researchers studied T cell populations in their work.
Meysman echoed the concern of how well researchers adopt the new system. He added that since many of the authors are prominent T cell researchers, he hopes that their use of it will encourage others to do so.
Another obstacle to adoption, Meysman said, could be researchers like himself who use computational pipelines that use the categorical nomenclature. “We are currently at the moment exploring if we can adjust these to the new definitions,” he said. “As long as there isn't this uptake within the computational tools, then I think it will be much more challenging for the broader researchers that are using these tools to actually switch to this methodology.”
While transitioning T cell nomenclature may take time in the research community for several reasons and the authors admit it is likely that changes will need to be made, they are hopeful that researchers will consider the new system. Currently, a subgroup of the authors plans to participate in a review of the suggested naming system in three years, where they hope to incorporate recommendations from scientists who have used the system and any advancements in T cell biology.
“I'm not 100 percent convinced yet that the solution that they propose is going to be the be all and end all,” Mesyman said. “But for the most part, I think they have done a good job at least of, say, pulling apart these different things that had been tangled together in the older definitions.”
- Masopust D, et al. Guidelines for T cell nomenclature. Nat Rev Immunol. 2025.
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