title: Trogocytosis is a gateway to characterize functional diversity in melanoma-specific CD8+ T cell clones.
abstract: Trogocytosis, the transfer of membrane patches from target to immune effector cells, is a signature of tumor-T cell interaction. In this study, we used the trogocytosis phenomenon to study functional diversity within tumor-specific T cell clones with identical TCR specificity. MART-1(26-35)-specific CD8 T cell clones, which differed in their trogocytosis capacity (low [2D11], intermediate [2G1], high [2E2]), were generated from melanoma patients. Functional evaluation of the clones showed that the percentage of trogocytosis-capable T cells closely paralleled each clone's IFN-γ and TNF-α production, lysosome degranulation, and lysis of peptide-pulsed targets and unmodified melanoma. The highly cytotoxic 2E2 clone displayed the highest TCR peptide binding affinity, whereas the low-activity 2D11 clone showed TCR binding to peptide-MHC in a CD8-dependent manner. TCR analysis revealed Vβ16 for clones 2E2 and 2G1 and Vβ14 for 2D11. When peptide-affinity differences were bypassed by nonspecific TCR stimulation, clones 2E2 and 2D11 still manifested distinctive signaling patterns. The high-activity 2E2 clone displayed prolonged phosphorylation of ribosomal protein S6, an integrator of MAPK and AKT activation, whereas the low-activity 2D11 clone generated shorter and weaker phosphorylation. Screening the two clones with identical TCR Vβ by immunoreceptor array showed higher phosphorylation of NK, T, and B cell Ag (NTB-A), a SLAM family homophilic receptor, in clone 2E2 compared with 2G1. Specific blocking of NTB-A on APCs markedly reduced cytokine production by CD8 lymphocytes, pointing to a possible contribution of NTB-A costimulation to T cell functional diversity. This finding identifies NTB-A as a potential target for improving anti-cancer immunotherapy.
authors.affiliation: Sharett Institute of Oncology, Hadassah Medical Organization, Jerusalem 91120, Israel.
authors.forename: Ronny
authors.initials: R
authors.lastname: Uzana
authors.forename: Galit
authors.initials: G
authors.lastname: Eisenberg
authors.forename: Yael
authors.initials: Y
authors.lastname: Sagi
authors.forename: Shoshana
authors.initials: S
authors.lastname: Frankenburg
authors.forename: Sharon
authors.initials: S
authors.lastname: Merims
authors.forename: Ninette
authors.initials: N
authors.lastname: Amariglio
authors.forename: Eitan
authors.initials: E
authors.lastname: Yefenof
authors.forename: Tamar
authors.initials: T
authors.lastname: Peretz
authors.forename: Arthur
authors.initials: A
authors.lastname: Machlenkin
authors.forename: Michal
authors.initials: M
authors.lastname: Lotem
mesh_terms: D017951:Antigen Presentation / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000276:immunology* / Q000473:pathology; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002999:Clone Cells; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods; D000939:Epitopes / Q000096:biosynthesis / Q000502:physiology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D015789:HLA-A2 Antigen / Q000096:biosynthesis / Q000502:physiology; D006801:Humans; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008546:Melanoma, Experimental / Q000276:immunology* / Q000473:pathology* / Q000556:secondary; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000502:physiology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism / Q000473:pathology
chemical_list: D000939:Epitopes; D018984:Epitopes, T-Lymphocyte; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; C105787:MART-1-Melan-A(27-35) epitope; D009363:Neoplasm Proteins