title: Human gammadelta T lymphocytes exert natural and IL-2-induced cytotoxicity to neuroblastoma cells.
abstract: Human gammadelta T lymphocytes play an important role in nonadaptive reactions to infection and early tumor defense. This is the first report that freshly isolated, native gammadelta T cells of some healthy donors can kill human neuroblastoma cells to varying degrees. Their killing ability was increased and maintained during expansion and cultivation with interleukin-2 (IL-2; 400 IU/mL) for as long as 30 days (100% specific lysis at an effector-to-target cell (E:T) ratio of 20:1). gammadelta T lymphocytes without this spontaneous killing ability gained a specific cytolytic activity of 81% +/- 10.4% SD after stimulation with IL-2 for 24 hours. gammadelta cells were isolated from peripheral blood by positive enrichment (using a magnetic cell sorting system; purity, 95.2% +/- 3.2% SD, n = 21). High natural cytotoxic activity against human neuroblastoma cell lines (>50% specific lysis at an E:T ratio of 20:1) was exhibited by one of 11 donors, whereas two of 11 showed medium cytotoxicity (30% to 50% specific lysis). Eight of 11 donors showed very slight or no lytic activity against human neuroblastoma cells (<30% specific lysis). gammadelta T cells were also cytotoxic against Daudi (32.7% specific lysis at an E:T ratio of 20:1), Raji (10.3%), Colo 205 (23.1%), A 204 (54%), K 562 (100%), and SK-N-MC (100%) cells. Isolated gammadelta T cells were grown in Iscove modified Dulbecco medium with IL-2 (400 IU/mL). Increased cell proliferation (38.5% to 182%) was induced with phytohemagglutinin, IL-15, Clodronat, OKT3, or various combinations of these. Results of cold target inhibition assays suggest a natural killer-like activity of the gammadelta T-cell killing mechanism. Peptidase or papain render neuroblastoma cells unsusceptible to gammadelta T-cell killing, suggesting the involvement of antigen peptide(s) in the process of neuroblastoma cell killing. Treatment with acid phosphatase reduced specific lysis by 66.5% +/- 34.1% SD, which suggests a binding to phosphorylated neuroblastoma cell-surface structures in the killing mechanism of gammadelta T cells. Heat shock did not affect the extent of neuroblastoma killing by gammadelta cells. Recognition of neuroblastoma cells by gammadelta cytotoxic T lymphocytes is negatively regulated by major histocompatibility complex I receptors. Evidence for natural and inducible cell cytotoxicity of gammadelta T cells against human neuroblastoma cells, easy propagation, purification, and missing alloreactivity in mixed lymphocytes cultures indicates a role for this subpopulation of T lymphocytes in adoptive immunotherapy.
authors.affiliation: Department of Hematology and Oncology, Children's Hospital, University of Tübingen, Germany.
authors.forename: K E
authors.initials: KE
authors.lastname: Schilbach
authors.forename: A
authors.initials: A
authors.lastname: Geiselhart
authors.forename: J T
authors.initials: JT
authors.lastname: Wessels
authors.forename: D
authors.initials: D
authors.lastname: Niethammer
authors.forename: R
authors.initials: R
authors.lastname: Handgretinger
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000912:Antibodies, Neoplasm / Q000276:immunology*; D017209:Apoptosis; D002455:Cell Division; D004002:Clodronic Acid / Q000494:pharmacology; D002999:Clone Cells; D005434:Flow Cytometry; D006801:Humans; D007167:Immunotherapy; D007376:Interleukin-2 / Q000276:immunology* / Q000494:pharmacology; D009447:Neuroblastoma / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000145:classification / Q000187:drug effects / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; D007376:Interleukin-2; D004002:Clodronic Acid