title: Loss of Fas (CD95/APO-1) expression by antigen-specific cytotoxic T cells is reversed by inhibiting DNA methylation.
abstract: Elimination of clonally expanded peripheral CD8 T cells was thought to involve apoptosis induction mediated principally by TNF, but recently Fas (CD95/APO-1) has been shown to play a role in certain responses. Here we study Fas expression and sensitivity to its ligation on murine CD8 cells specific for the CW3 antigen expressed by transfected P815 cells. Fas was progressively downregulated after successive in vitro restimulations of antigen-specific CD8 cells, until clones became Fas negative and totally resistant to the effects of recombinant Fas ligand. In contrast, Fas expression by in vivo restimulated antigen-specific cells did not diminish. Loss of Fas expression in vitro was not totally irreversible, since it could be reinduced by inhibition of DNA methylation. Understanding how Fas may be differentially regulated in vivo and in vitro is an important issue for the optimal manipulation of T cells for adoptive immunotherapy protocols.
authors.affiliation: Laboratory of Tumour Immunology, Division of Oncology, University Hospital Geneva, CH-1211 Geneva 14, Switzerland. Paul.Walker@hcuge.ch
authors.forename: P R
authors.initials: PR
authors.lastname: Walker
authors.forename: T
authors.initials: T
authors.lastname: Calzascia
authors.forename: V
authors.initials: V
authors.lastname: Schnuriger
authors.forename: D
authors.initials: D
authors.lastname: Chalmers
authors.forename: P
authors.initials: P
authors.lastname: Saas
authors.forename: P Y
authors.initials: PY
authors.lastname: Dietrich
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002999:Clone Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects*; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053222:Fas Ligand Protein; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000502:physiology*; D015236:HLA-C Antigens / Q000235:genetics / Q000276:immunology; D016219:Immunotherapy, Adoptive; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology; D051379:Mice; D008811:Mice, Inbred DBA; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D015236:HLA-C Antigens; C038653:HLA-C*03 antigen; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D019014:fas Receptor; D000077209:Decitabine; D001374:Azacitidine