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Lentivirus-Induced Dendritic Cells for Immunization Against High-Risk WT1 + Acute Myeloid Leukemia

2013; Mary Ann Liebert, Inc.; Volume: 24; Issue: 2 Linguagem: Inglês

10.1089/hum.2012.128

1557-7422

Bala Sai Sundarasetty, Vijay Kumar Singh, Gustavo Salguero, Robert Geffers, Mareike Rickmann, Laura Macke, Sylvia Borchers, Constança Figueiredo, Axel Schambach, Urban Gullberg, Elena Provasi, Chiara Bonini, Arnold Ganser, Thomas Woelfel, Renata Stripecke,

Immunotherapy and Immune Responses

Wilms' tumor 1 antigen (WT1) is overexpressed in acute myeloid leukemia (AML), a high-risk neoplasm warranting development of novel immunotherapeutic approaches. Unfortunately, clinical immunotherapeutic use of WT1 peptides against AML has been inconclusive. With the rationale of stimulating multiantigenic responses against WT1, we genetically programmed long-lasting dendritic cells capable of producing and processing endogenous WT1 epitopes. A tricistronic lentiviral vector co-expressing a truncated form of WT1 (lacking the DNA-binding domain), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-4 (IL-4) was used to transduce human monocytes ex vivo. Overnight transduction induced self-differentiation of monocytes into immunophenotypically stable "SmartDC/tWT1" (GM-CSF+, IL-4+, tWT1+, IL-6+, IL-8+, TNF-α+, MCP-1+, HLA-DR+, CD86+, CCR2+, CCR5+) that were viable for 3 weeks in vitro. SmartDC/tWT1 were produced with peripheral blood mononuclear cells (PBMC) obtained from an FLT3-ITD+ AML patient and surplus material from a donor lymphocyte infusion (DLI) and used to expand CD8+ T cells in vitro. Expanded cytotoxic T lymphocytes (CTLs) showed antigen-specific reactivity against WT1 and against WT1+ leukemia cells. SmartDC/tWT1 injected s.c. into Nod.Rag1−/−.IL2rγc−/− mice were viable in vivo for more than three weeks. Migration of human T cells (huCTLs) to the immunization site was demonstrated following adoptive transfer of huCTLs into mice immunized with SmartDC/tWT1. Furthermore, SmartDC/tWT1 immunization plus adoptive transfer of T cells reactive against WT1 into mice resulted in growth arrest of a WT1+ tumor. Gene array analyses of SmartDC/tWT1 demonstrated upregulation of several genes related to innate immunity. Thus, SmartDC/tWT1 can be produced in a single day of ex vivo gene transfer, are highly viable in vivo, and have great potential for use as immunotherapy against malignant transformation overexpressing WT1. Sundarasetty and colleagues generate long-lasting, self-differentiated myeloid-derived antigen-presenting cells reactive against tumors (SmartDC) expressing a truncated form of Wilms' tumor 1 antigen (tWT1). SmartDC/tWT1 generated from a patient with acute myeloid leukemia (AML) efficiently stimulated expansion and activation of anti-WT1 cytotoxic responses against primary blasts obtained from the patient. SmartDC/tWT1 injected into a mouse model of adoptive T cell transfer remained viable in vivo for more than 3 weeks, and it was capable of attracting cytotoxic T cells.