Dendritic cells and regulatory T cells reinforce immunosuppression in pancreatic tumors

Within pancreatic tumors, two cell types appear to help each other sustain an environment that shields the cancer from immune attack. Using single-cell RNA sequencing and spatial transcriptomics on pancreatic cancer tissue, researchers mapped the interactions among immune cells in the tumor microenvironment and found that regulatory T cells (Tregs) and dendritic cells (DCs) sit unusually close to one another. The study, published open access in Cell Communication and Signaling, also identified candidate cytokines that appear to carry the signals between these cell populations.

The proximity alone did not explain the relationship, so the team turned to laboratory experiments with differentiated dendritic cells and Tregs. When the two cell types were combined, Tregs pushed dendritic cells into the mature mregDC state, a maturation program associated with specific regulatory functions. In the reverse direction, mregDCs enhanced the proliferation and activation of Tregs. Together, these results point to a reinforcing feedback loop: each cell type promotes the other’s development or activity, and the loop’s location within the tumor suggests it may help maintain the immunosuppressive conditions that limit effective anti-tumor immunity in pancreatic cancer.

The researchers also identified the cytokines that appear to mediate this crosstalk, naming IL15 and Tnfsf11 as the signals connecting DCs and Tregs. Because the loop depends on these particular molecules, the authors suggest that blocking IL15 and Tnfsf11 might disrupt the DC–Treg interactions. Importantly, they report that such a blockade may spare CD8 T-cell activation, the arm of the immune system responsible for killing tumor cells, meaning the intervention could in principle weaken the suppressive circuit without damaging the desired immune response.

The findings come from a combination of human tissue analysis and cell-based experiments, and the authors frame the feedback loop as something that “may support” the immunosuppressive microenvironment rather than a definitively proven driver of tumor progression. The article is currently shared as an accepted, peer-reviewed manuscript subject to further edits before the final version of record.

Subject of Research: Immune cell interactions between dendritic cells and regulatory T cells in the pancreatic tumor microenvironment

Article Title: MregDCs preferentially associate with regulatory T cells in the pancreatic tumor microenvironment

Article References: Hao, Y., Yosefov-Levi, O., Arcila-Barrera, S., Shovman, Y., Sarusi-Portuguez, A., Holiar, V., Kunukcu, H. B., Biton, M., Hwang, W. L., Cheng, J., Tornovsky-Babeay, S., & Parnas, O. (2026). MregDCs preferentially associate with regulatory T cells in the pancreatic tumor microenvironment. Cell Communication and Signaling. https://doi.org/10.1186/s12964-026-03304-1

Image Credits: AI Generated

DOI: 10.1186/s12964-026-03304-1

Keywords: pancreatic cancer, tumor microenvironment, regulatory T cells, dendritic cells, mregDCs, single-cell RNA-seq, spatial transcriptomics, IL15, Tnfsf11, immunosuppression, cytokines, CD8 T cells