Abstract
Foxp3+ regulatory T cells (Tregs) are often highly enriched within the tumor-infiltrating T cell pool. Using a well-characterised model of carcinogen-induced fibrosarcomas we show that the enriched tumor-infiltrating Treg population comprises largely of CXCR3+ T-bet+ 'TH1-like' Tregs which are thymus-derived Helios+ cells. Whilst IL-2 maintains homeostatic ratios of Tregs in lymphoid organs, we found that the perturbation in Treg frequencies in tumors is IL-2 independent. Moreover, we show that the TH1 phenotype of tumor-infiltrating Tregs is dispensable for their ability to influence tumor progression. We did however find that unlike Tconvs, the majority of intra-tumoral Tregs express the activation markers CD69, CD25, ICOS, CD103 and CTLA4 and are significantly more proliferative than Tconvs. Moreover, we have found that CD69+ Tregs are more suppressive than their CD69- counterparts. Collectively, these data indicate superior activation of Tregs in the tumor microenvironment, promoting their suppressive ability and selective proliferation at this site.
Original language | English |
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Pages (from-to) | 24649-59 |
Number of pages | 11 |
Journal | Oncotarget |
Volume | 6 |
Issue number | 28 |
DOIs | |
Publication status | Published - 22 Sep 2015 |