title: Tumor-specific CD8+ T cells expressing interleukin-12 eradicate established cancers in lymphodepleted hosts.
abstract: T-cell-based immunotherapies can be effective in the treatment of large vascularized tumors, but they rely on adoptive transfer of substantial numbers ( approximately 20 million) of tumor-specific T cells administered together with vaccination and high-dose interleukin (IL)-2. In this study, we report that approximately 10,000 T cells gene-engineered to express a single-chain IL-12 molecule can be therapeutically effective against established tumors in the absence of exogenous IL-2 and vaccine. Although IL-12-engineered cells did not perist long-term in hosts, they exhibited enhanced functionality and were detected in higher numbers intratumorally along with increased numbers of endogenous natural killer and CD8(+) T cells just before regression. Importantly, transferred T cells isolated from tumors stably overproduced supraphysiologic amounts of IL-12, and the therapeutic effect of IL-12 produced within the tumor microenvironment could not be mimicked with high doses of exogenously provided IL-12. Furthermore, antitumor effects could be recapitulated by engineering wild-type open-repertoire splenocytes to express both the single-chain IL-12 and a recombinant tumor-specific T-cell receptor (TCR), but only when individual cells expressed both the TCR and IL-12, indicating that arrested migration of T cells at the tumor site was required for their activities. Successful tumor eradication was dependent on a lymphodepleting preconditioning regimen that reduced the number of intratumoral CD4(+) Foxp3(+) T regulatory cells. Our findings reveal an approach to genetically modify T cells to reduce the cell number needed, eliminate the need for vaccines or systemic IL-2, and improve immunotherapy efficacy based on adoptive transfer of gene-engineered T cells.
authors.affiliation: Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD, USA. kerkars@mail.nih.gov
authors.forename: Sid P
authors.initials: SP
authors.lastname: Kerkar
authors.forename: Pawel
authors.initials: P
authors.lastname: Muranski
authors.forename: Andrew
authors.initials: A
authors.lastname: Kaiser
authors.forename: Andrea
authors.initials: A
authors.lastname: Boni
authors.forename: Luis
authors.initials: L
authors.lastname: Sanchez-Perez
authors.forename: Zhiya
authors.initials: Z
authors.lastname: Yu
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Palmer
authors.forename: Robert N
authors.initials: RN
authors.lastname: Reger
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Borman
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Richard A
authors.initials: RA
authors.lastname: Morgan
authors.forename: Luca
authors.initials: L
authors.lastname: Gattinoni
authors.forename: Steven A
authors.initials: SA
authors.lastname: Rosenberg
authors.forename: Giorgio
authors.initials: G
authors.lastname: Trinchieri
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Restifo
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D016219:Immunotherapy, Adoptive / Q000379:methods*; D018664:Interleukin-12 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology* / Q000378:metabolism; D008546:Melanoma, Experimental / Q000276:immunology / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D015202:Protein Engineering / Q000379:methods; D012190:Retroviridae / Q000235:genetics; D014161:Transduction, Genetic
chemical_list: D018664:Interleukin-12