title: Lack of effector cell function and altered tetramer binding of tumor-infiltrating lymphocytes.
abstract: Tumor-specific CD8 T cell responses to MCA102 fibrosarcoma cells expressing the cytotoxic T cell epitope gp33 from lymphocytic choriomeningitis virus were studied. MCA102(gp33) tumors grew progressively in C57BL/6 mice, despite induction of peripheral gp33-tetramer(+) T cells that were capable of mediating antiviral protection, specific cell rejection, and concomitant tumor immunity. MCA102(gp33) tumors were infiltrated with a high number ( approximately 20%) of CD11b(+)CD11c(-) macrophage-phenotype cells that were able to cross-present the gp33 epitope to T cells. Tumor-infiltrating CD8 T cells exhibited a highly activated phenotype but lacked effector cell function. Strikingly, a significant portion of tumor-infiltrating lymphocytes expressed TCRs specific for gp33 but bound MHC tetramers only after cell purification and a 24-h resting period in vitro. The phenomenon of "tetramer-negative T cells" was not restricted to tumor-infiltrating lymphocytes from MCA102(gp33) tumors, but was also observed when Ag-specific T cells derived from an environment with high Ag load were analyzed ex vivo. Thus, using a novel tumor model, allowing us to trace tumor-specific T cells at the single cell level in vivo, we demonstrate that the tumor microenvironment is able to alter the functional activity of T cells infiltrating the tumor mass.
authors.affiliation: Institute of Medical Microbiology and Hygiene, Department of Immunology, University of Freiburg, Hermann-Herdfer-Strasse 11, D-79104 Freiburg, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Blohm
authors.forename: Evelyn
authors.initials: E
authors.lastname: Roth
authors.forename: Kathrin
authors.initials: K
authors.lastname: Brommer
authors.forename: Tilman
authors.initials: T
authors.lastname: Dumrese
authors.forename: Felicia M
authors.initials: FM
authors.lastname: Rosenthal
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Pircher
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000235:genetics; D000956:Antigens, Viral / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D039481:CD11b Antigen / Q000096:biosynthesis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002469:Cell Separation; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D018984:Epitopes, T-Lymphocyte / Q000096:biosynthesis / Q000276:immunology; D005260:Female; D005354:Fibrosarcoma / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D006023:Glycoproteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D007113:Immunity, Innate / Q000235:genetics; D018655:Lymphocyte Count; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009368:Neoplasm Transplantation; D010446:Peptide Fragments / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis; D014407:Tumor Cells, Cultured; D014764:Viral Proteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*
chemical_list: D000956:Antigens, Viral; D039481:CD11b Antigen; D018984:Epitopes, T-Lymphocyte; D006023:Glycoproteins; D015395:Histocompatibility Antigens Class I; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D014764:Viral Proteins; C094244:glycoprotein peptide 33-41, Lymphocytic choriomeningitis virus