title: Radiotherapy combined with intratumoral dendritic cell vaccination enhances the therapeutic efficacy of adoptive T-cell transfer.
abstract: Treatment of C57BL/6 mice with cyclophosphamide (100 mg/kg) and fludarabine (200 mg/kg) induced nonmyeloablative lymphodepletion without inhibiting D5 melanoma tumor growth. Using this model, we found that induction of lymphopenia before adoptive transfer of ex vivo anti-CD3/CD28 activated and interleukin-2 expanded D5-G6 tumor draining lymph node cells enhanced the antitumor efficacy of the infused cells in both pulmonary metastases and subcutaneous D5 bearing mice. However, induction of lymphopenia did not promote intratumoral or extratumoral proliferation or accumulation of the infused cells. We have previously shown that radiotherapy enhances the therapeutic efficacy of intratumoral unpulsed dendritic cell vaccination in subcutaneous murine tumor models by augmenting the induction of antitumor cellular immune responses. Here, we confirmed this finding in a murine metastatic melanoma liver tumor model. Furthermore, local tumor irradiation combined with intratumoral dendritic cell administration significantly enhanced the therapeutic efficacy of tumor-reactive T cell adoptive transfer in this lymphodepleted liver tumor model. This was evident by reduced liver tumor size, decreased incidence of spontaneous intra-abdominal metastasis, and prolonged survival, resulting in 46% of mice cured. This enhanced antitumor activity was associated with a selective increase in proliferation, accumulation, and function of CD4+ rather than CD8+ infused cells. This multimodality regimen may have translational applications for the treatment of human cancers.
authors.affiliation: Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0932, USA.
authors.forename: Seagal
authors.initials: S
authors.lastname: Teitz-Tennenbaum
authors.forename: Qiao
authors.initials: Q
authors.lastname: Li
authors.forename: Mary A
authors.initials: MA
authors.lastname: Davis
authors.forename: Kari
authors.initials: K
authors.lastname: Wilder-Romans
authors.forename: Janet
authors.initials: J
authors.lastname: Hoff
authors.forename: Mu
authors.initials: M
authors.lastname: Li
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Chang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000637:transplantation*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000637:transplantation*; D019496:Cancer Vaccines / Q000276:immunology; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000494:pharmacology; D003713:Dendritic Cells / Q000276:immunology / Q000637:transplantation*; D005260:Female; D007166:Immunosuppressive Agents / Q000494:pharmacology; D016219:Immunotherapy, Adoptive; D008113:Liver Neoplasms / Q000532:radiotherapy / Q000556:secondary / Q000628:therapy*; D008175:Lung Neoplasms / Q000532:radiotherapy / Q000556:secondary / Q000628:therapy*; D008198:Lymph Nodes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D008231:Lymphopenia / Q000139:chemically induced / Q000276:immunology; D008546:Melanoma, Experimental / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D014740:Vidarabine / Q000031:analogs & derivatives
chemical_list: D000970:Antineoplastic Agents; D019496:Cancer Vaccines; D007166:Immunosuppressive Agents; D003520:Cyclophosphamide; D014740:Vidarabine; C024352:fludarabine