title: Treatment-enhanced CD4+Foxp3+ glucocorticoid-induced TNF receptor family related high regulatory tumor-infiltrating T cells limit the effectiveness of cytokine-based immunotherapy.
abstract: Regulatory T cells can suppress activated CD4+ and CD8+ T effector cells and may serve as an impediment to spontaneous or therapeutic type 1 antitumor immunity. In a previous study, we observed minimal therapeutic impact, but significantly enhanced T cell cross-priming and lesional infiltration of tumor-reactive CD8+ T cells into established CMS4 sarcomas after combined treatment of BALB/c mice with rFLt3 ligand (rFL) and recombinant GM-CSF (rGM-CSF). In this study, we show that this cytokine regimen also results in the profound enhancement of CD4+ tumor-infiltrating lymphocytes (TIL) expressing FoxP3, IL-10, and TGF-beta mRNA, with 50 or 90% of CD4+ TIL coexpressing the CD25 and glucocorticoid-induced TNFR family related molecules, respectively. Intracellular staining for Foxp3 protein revealed that combined treatment with rFL plus rGM-CSF results in a significant increase in CD4+Foxp3+ T cells in the spleen of both control and tumor-bearing mice, and that nearly half of CD4+ TIL expressed this marker. In addition, CD4+ TIL cells were of an activated/memory (ICOS(high)CD62L(low)CD45RB(low)) phenotype and were capable of suppressing allospecific T cell proliferation and IFN-gamma production from (in vivo cross-primed) anti-CMS4 CD8+ T cells in vitro, via a mechanism at least partially dependent on IL-10 and TGF-beta. Importantly, in vivo depletion of CD4+ T cells resulted in the ability of previously ineffective, rFL plus rGM-CSF therapy-induced CD8+ T cells to now mediate tumor regression.
authors.affiliation: Department of Immunology, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, USA.
authors.forename: Aklile
authors.initials: A
authors.lastname: Berhanu
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.forename: Simon C
authors.initials: SC
authors.lastname: Watkins
authors.forename: Hideho
authors.initials: H
authors.lastname: Okada
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Storkus
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016207:Cytokines / Q000276:immunology / Q000627:therapeutic use; D051858:Forkhead Transcription Factors / Q000276:immunology*; D053450:Glucocorticoid-Induced TNFR-Related Protein / Q000276:immunology*; D007156:Immunologic Memory / Q000187:drug effects; D007167:Immunotherapy; D060889:Inducible T-Cell Co-Stimulator Protein; D008213:Lymphocyte Activation / Q000276:immunology; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology* / Q000473:pathology; D008565:Membrane Proteins / Q000276:immunology / Q000627:therapeutic use; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D015398:Signal Transduction / Q000276:immunology; D050378:T-Lymphocytes, Regulatory
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D016207:Cytokines; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D053450:Glucocorticoid-Induced TNFR-Related Protein; C556694:Icos protein, mouse; D060889:Inducible T-Cell Co-Stimulator Protein; D008565:Membrane Proteins; C084881:flt3 ligand protein