title: Tumor dormancy and cell signaling: anti-mu-induced apoptosis in human B-lymphoma cells is not caused by an APO-1-APO-1 ligand interaction.
abstract: Signal transduction initiated by crosslinking of antigen-specific receptors on T- and B-lymphoma cells induces apoptosis. In T-lymphoma cells, such crosslinking results in upregulation of the APO-1 ligand, which then interacts with induced or constitutively expressed APO-1, thereby triggering apoptosis. Here we show that crosslinking the membrane immunoglobulin on human lymphoma cells (Daudi) (that constitutively express APO-1) does not induce synthesis of APO-1 ligand. Further, a noncytotoxic fragment of anti-APO-1 antibody that blocks T-cell-receptor-mediated apoptosis in T-lymphoma cells does not block anti-mu-induced apoptosis. Hence, in B-lymphoma cells, apoptosis induced by signaling via membrane IgM is not mediated by the APO-1 ligand.
authors.affiliation: Department of Microbiology and Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas 75235, USA.
authors.forename: E
authors.initials: E
authors.lastname: Racila
authors.forename: R
authors.initials: R
authors.lastname: Hsueh
authors.forename: R
authors.initials: R
authors.lastname: Marches
authors.forename: T F
authors.initials: TF
authors.lastname: Tucker
authors.forename: P H
authors.initials: PH
authors.lastname: Krammer
authors.forename: R H
authors.initials: RH
authors.lastname: Scheuermann
authors.forename: J W
authors.initials: JW
authors.lastname: Uhr
mesh_terms: D017209:Apoptosis; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D006801:Humans; D007148:Immunoglobulin mu-Chains; D008024:Ligands; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000502:physiology*
chemical_list: D017931:DNA Primers; D007148:Immunoglobulin mu-Chains; D008024:Ligands; D011947:Receptors, Antigen, B-Cell; D019014:fas Receptor