Tumor-Infiltrating Regulatory T Cell Accumulation in the Tumor Microenvironment is Mediated by IL33/ST2 Signaling

The objective of this study is to compare transcriptional features in tumor-infiltrating (TI) regulatory T (Treg) cells with TI CD4+ conventional T (Tconv) cells, splenic Treg cells of tumor-bearing mice, splenic Tconv cells of tumor-bearing mice, splenic Treg cells of normal mice, or splenic Tconv cells of normal mice. A total of 5 × 10^5 TC-1 cells were intravenously injected into the tail vein of mice. At 3 weeks after tumor inoculation, tumor-bearing mice were sacrificed. The spleen and tumor from tumor-bearing mice and spleen of normal mice were harvested and processed into single cells. CD4+ T cells were enriched using a CD4+ T cell isolation kit by negative selection. Pure CD4+GFP+ Treg and CD4+GFP- Tconv populations were obtained through sorting using a FACSAria II.