Researchers from the University Hospital Bonn (UKB) and the University of Bonn have developed a new laboratory model that enables scientists to generate and study follicular regulatory T (Tfr) cells, a specialized group of immune cells responsible for controlling antibody responses. The breakthrough is expected to accelerate research into autoimmune diseases, vaccine responses, and immune regulation. The findings have been published in the journal Cellular & Molecular Immunology.
Tfr cells play a critical role in maintaining the balance of the immune system. Located within germinal centers of lymphoid organs such as the lymph nodes, spleen, and tonsils, these cells regulate the activity of follicular T helper (Tfh) cells and B cells, ensuring that antibody production is strong enough to fight infections while preventing excessive immune reactions that could damage healthy tissues.
Until now, studying Tfr cells has been challenging because they are difficult to isolate and maintain under laboratory conditions. To overcome this limitation, the Bonn research team established a reliable in vitro model that allows Tfr cells to be generated from precursor CD4- T helper cells and examined under controlled experimental conditions.
Using the new model, the researchers identified important molecular pathways that regulate the development of Tfr cells. They discovered that the growth factor transforming growth factor-beta (TGF-β) is both necessary and sufficient to activate the genetic program required for Tfr cell formation. In contrast, the immune signaling molecule interleukin-2 (IL-2) acts in the opposite direction, limiting Tfr cell differentiation. According to the researchers, the balanced interaction between TGF-β and IL-2 is essential for producing fully functional Tfr cells.
The study also identified the transcription factor c-Maf as a crucial regulator of Tfr cell differentiation. When c-Maf was absent, developing cells failed to acquire the defining characteristics of mature follicular regulatory T cells, highlighting its importance in immune cell development.
To confirm the biological relevance of their laboratory-generated cells, the scientists performed functional experiments showing that the newly generated Tfr cells effectively suppressed Tfh cell-driven activation of B cells and reduced the production of specific antibody classes. These findings demonstrate that the laboratory-produced cells closely resemble naturally occurring Tfr cells.
According to the research team, the new model provides an important experimental platform for understanding how antibody responses are regulated under normal conditions and how disruptions in this balance contribute to autoimmune disorders and abnormal immune reactions.
Beyond its immediate research applications, the model may support future studies aimed at improving vaccines, developing immune-modulating therapies, and understanding diseases characterized by excessive or defective antibody production. The study was funded in part by the German Research Foundation (DFG).
Reference :
Bach L, et al. TGF-β and IL-2 differentially shape T follicular regulatory cell differentiation and stability in vitro. Cellular & Molecular Immunology (2026).
DOI: 10.1038/s41423-026-01440-9
