title: Activation-induced cell death limits effector function of CD4 tumor-specific T cells.
abstract: A number of studies have documented a critical role for tumor-specific CD4(+) cells in the augmentation of immunotherapeutic effector mechanisms. However, in the context of an extensive tumor burden, chronic stimulation of such CD4(+) T cells often leads to the up-regulation of both Fas and Fas ligand, and coexpression of these molecules can potentially result in activation-induced cell death and the subsequent loss of effector activity. To evaluate the importance of T cell persistence in an experimental model of immunotherapy, we used DO11 Th1 cells from wild-type, Fas-deficient, and Fas ligand-deficient mice as effector populations specific for a model tumor Ag consisting of an OVA-derived transmembrane fusion protein. We found that the prolonged survival of Fas-deficient DO11 Th1 cells led to a more sustained tumor-specific response both in vitro and in vivo. Importantly, both Fas- and Fas ligand-deficient Th1 cells delayed tumor growth and cause regression of established tumors more effectively than wild-type Th1 cells, indicating that resistance to activation-induced cell death significantly enhances T cell effector activity.
authors.affiliation: Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Saff
authors.forename: Elena S
authors.initials: ES
authors.lastname: Spanjaard
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Hohlbaum
authors.forename: Ann
authors.initials: A
authors.lastname: Marshak-Rothstein
mesh_terms: D000818:Animals; D017209:Apoptosis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D053222:Fas Ligand Protein; D005260:Female; D008213:Lymphocyte Activation; D008297:Male; D008562:Membrane Glycoproteins / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000276:immunology*; D010047:Ovalbumin / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D019014:fas Receptor / Q000502:physiology
chemical_list: D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D019014:fas Receptor; D010047:Ovalbumin