title: Virus-specific cytotoxic CD4+ T cells for the treatment of EBV-related tumors.
abstract: Although adoptive immunotherapy with CD8(+) CTL is providing clinically relevant results against EBV-driven malignancies, the effector role of CD4(+) T cells has been poorly investigated. We addressed this issue in a lymphoblastoid cell line-induced mouse model of posttransplant lymphoproliferative disease (PTLD) by comparing the therapeutic efficacy of EBV-specific CD4(+) and CD8(+) T cell lines upon adoptive transfer. CD4(+) T cells disclosed a long-lasting and stronger proliferative potential than CD8(+) T cells, had a similar activation and differentiation marker profile, efficiently killed their targets in a MHC class II-restricted manner, and displayed a lytic machinery comparable to that of cognate CD8(+) T cells. A detailed analysis of Ag specificity revealed that CD4(+) T cells potentially target EBV early lytic cycle proteins. Nonetheless, when assessed for the relative therapeutic impact after in vivo transfer, CD4(+) T cells showed a reduced activity compared with the CD8(+) CTL counterpart. This feature was apparently due to a strong and selective downmodulation of MHC class II expression on the tumor cells surface, a phenomenon that could be reverted by the demethylating agent 5-aza-2'-deoxycytidine, thus leading to restoration of lymphoblastoid cell line recognition and killing by CD4(+) T cells, as well as to a more pronounced therapeutic activity. Conversely, immunohistochemical analysis disclosed that HLA-II expression is fully retained in human PTLD samples. Our data indicate that EBV-specific cytotoxic CD4(+) T cells are therapeutic in mice bearing PTLD-like tumors, even in the absence of CD8(+) T cells. These findings pave the way to use cultures of pure CD4(+) T cells in immunotherapeutic approaches for EBV-related malignancies.
authors.affiliation: Department of Oncology and Surgical Sciences, University of Padova, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Merlo
authors.forename: Riccardo
authors.initials: R
authors.lastname: Turrini
authors.forename: Sara
authors.initials: S
authors.lastname: Bobisse
authors.forename: Rita
authors.initials: R
authors.lastname: Zamarchi
authors.forename: Rita
authors.initials: R
authors.lastname: Alaggio
authors.forename: Riccardo
authors.initials: R
authors.lastname: Dolcetti
authors.forename: Josef
authors.initials: J
authors.lastname: Mautner
authors.forename: Paola
authors.initials: P
authors.lastname: Zanovello
authors.forename: Alberto
authors.initials: A
authors.lastname: Amadori
authors.forename: Antonio
authors.initials: A
authors.lastname: Rosato
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000821:virology; D002144:Callithrix; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods; D015536:Down-Regulation / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D020031:Epstein-Barr Virus Infections / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D006684:HLA-DR Antigens / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D016219:Immunotherapy, Adoptive / Q000379:methods; D016393:Lymphoma, B-Cell / Q000276:immunology / Q000473:pathology / Q000628:therapy; D051379:Mice; D016513:Mice, SCID
chemical_list: D018984:Epitopes, T-Lymphocyte; D006684:HLA-DR Antigens; D015395:Histocompatibility Antigens Class I