title: Tumor-reactive CD8+ early effector T cells identified at tumor site in primary and metastatic melanoma.
abstract: CD8(+) T cells at the earliest stage of effector generation have not been identified at tumor site of melanoma patients. Such early effectors, if present, should be characterized by a specific phenotype, distinct from that expressed at later stages of the antigen-induced differentiation program, by short-lived effector cells, memory precursors, and terminal effectors. Here, we show that neoplastic tissues from primary and metastatic lesions of melanoma patients contain a subset of CD8(+) T cells expressing FOXP3. CD8(+) FOXP3(+) CD25(+) T lymphocytes were found in tumor-invaded lymph nodes (TILN), s.c. metastases, and advanced primary lesions. Their frequency was significantly higher in TILN compared with tumor-free lymph nodes or with peripheral blood and in primary tumors compared with TILN. CD8(+) FOXP3(+) T cells did not express markers of regulatory [CTLA-4, CCL4, interleukin-10 (IL-10), transforming growth factor-β1], exhausted (PD-1), or senescent (CD57) CD8(+) T lymphocytes. Instead, this subset showed an antigen-experienced "EM1" phenotype (CCR7(-) CD45RA(-) CD28(+) CD27(+)) and exhibited a CD127(-), KLRG1(-), HLA-DR(+), CD38(+), T-bet(+), perforin(+) "early effector" profile predicted by current models. CD8(+) FOXP3(+) T cells produced IFN-γ on short in vitro activation, recognized autologous tumor by CD107a mobilization, and expressed Ki-67 on ex vivo analysis. In response to autologous tumor plus IL-2/IL-15, the CD8(+) FOXP3(+) T cells proliferated promptly and showed competence for differentiation (downregulation of CD27 and upregulation of T-bet). These results suggest development of early phases of antitumor immunity even in advanced melanoma. Moreover, the CD8(+) FOXP3(+) "early effector" subset may be an invaluable tool for monitoring immunity at tumor site.
authors.affiliation: Human Tumors Immunobiology Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. andrea.anichini@istitutotumori.mi.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Anichini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Molla
authors.forename: Claudia
authors.initials: C
authors.lastname: Vegetti
authors.forename: Ilaria
authors.initials: I
authors.lastname: Bersani
authors.forename: Roberta
authors.initials: R
authors.lastname: Zappasodi
authors.forename: Flavio
authors.initials: F
authors.lastname: Arienti
authors.forename: Fernando
authors.initials: F
authors.lastname: Ravagnani
authors.forename: Andrea
authors.initials: A
authors.lastname: Maurichi
authors.forename: Roberto
authors.initials: R
authors.lastname: Patuzzo
authors.forename: Mario
authors.initials: M
authors.lastname: Santinami
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Pircher
authors.forename: Massimo
authors.initials: M
authors.lastname: Di Nicola
authors.forename: Roberta
authors.initials: R
authors.lastname: Mortarini
mesh_terms: D015153:Blotting, Western; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D002454:Cell Differentiation; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007156:Immunologic Memory / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology; D008207:Lymphatic Metastasis; D008213:Lymphocyte Activation / Q000502:physiology; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D008545:Melanoma / Q000276:immunology* / Q000556:secondary; D010641:Phenotype; D012878:Skin Neoplasms / Q000276:immunology* / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism / Q000473:pathology
chemical_list: D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors