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Human Langerhans cells use an IL-15R-?/IL-15/pSTAT5-dependent mechanism to break T-cell tolerance against the self-differentiation tumor antigen WT1.

ABSTRACT: Human CD34(+) progenitor-derived Langerhans-type dendritic cells (LCs) are more potent stimulators of T-cell immunity against tumor and viral antigens in vitro than are monocyte-derived DCs (moDCs). The exact mechanisms have remained elusive until now, however. LCs synthesize the highest amounts of IL-15R-? mRNA and protein, which binds IL-15 for presentation to responder lymphocytes, thereby signaling the phosphorylation of signal transducer and activator of transcription 5 (pSTAT5). LCs electroporated with Wilms tumor 1 (WT1) mRNA achieve sufficiently sustained presentation of antigenic peptides, which together with IL-15R-?/IL-15, break tolerance against WT1 by stimulating robust autologous, WT1-specific cytolytic T-lymphocytes (CTLs). These CTLs develop from healthy persons after only 7 days' stimulation without exogenous cytokines and lyse MHC-restricted tumor targets, which include primary WT1(+) leukemic blasts. In contrast, moDCs require exogenous rhuIL-15 to phosphorylate STAT5 and attain stimulatory capacity comparable to LCs. LCs therefore provide a more potent costimulatory cytokine milieu for T-cell activation than do moDCs, thus accounting for their superior stimulation of MHC-restricted Ag-specific CTLs without need for exogenous cytokines. These data support the use of mRNA-electroporated LCs, or moDCs supplemented with exogenous rhuIL-15, as vaccines for cancer immunotherapy to break tolerance against self-differentiation antigens shared by tumors.

SUBMITTER: Romano E

PROVIDER: S-EPMC3369609 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature

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Human Langerhans cells use an IL-15R-α/IL-15/pSTAT5-dependent mechanism to break T-cell tolerance against the self-differentiation tumor antigen WT1.

Romano Emanuela E Cotari Jesse W JW Barreira da Silva Rosa R Betts Brian C BC Chung David J DJ Avogadri Francesca F Fink Mitsu J MJ St Angelo Erin T ET Mehrara Babak B Heller Glenn G Münz Christian C Altan-Bonnet Gregoire G Young James W JW

Blood 20120417 22

Human CD34(+) progenitor-derived Langerhans-type dendritic cells (LCs) are more potent stimulators of T-cell immunity against tumor and viral antigens in vitro than are monocyte-derived DCs (moDCs). The exact mechanisms have remained elusive until now, however. LCs synthesize the highest amounts of IL-15R-α mRNA and protein, which binds IL-15 for presentation to responder lymphocytes, thereby signaling the phosphorylation of signal transducer and activator of transcription 5 (pSTAT5). LCs electr ...[more]

PMID: 22510877

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Project description:Engineered autologous acute myeloid leukemia (AML) cells present multiple leukemia-associated and patient-specific antigens and as such hold promise as immunotherapeutic vaccines. However, prior vaccines have not reliably induced effective antileukemic immunity, in part because AML blasts have immune inhibitory effects and lack expression of the critical costimulatory molecule CD80. To enhance induction of leukemia-specific cytolytic activity, 32Dp210 murine AML cells were engineered to express either CD80 alone, or the immunostimulatory cytokine interleukin-15 (IL-15) with its receptor ? (IL-15R?), or heterodimeric IL-15/IL-15R? together with CD80 and tested as irradiated cell vaccines. IL-15 is a ?c-chain cytokine, with unique properties suited to stimulating antitumor immunity, including stimulation of both natural killer and CD8+ memory T cells. Coexpression of IL-15 and IL-15R? markedly increases IL-15 stability and secretion. Non-tumor-bearing mice vaccinated with irradiated 32Dp210-IL-15/IL-15R?/CD80 and challenged with 32Dp210 leukemia had greater survival than did mice treated with 32Dp210-CD80 or 32Dp210-IL-15/IL-15R? vaccines, whereas no unvaccinated mice inoculated with leukemia survived. In mice with established leukemia, treatment with 32Dp210-IL-15/IL-15R?/CD80 vaccination stimulated unprecedented antileukemic immunity enabling 80% survival, an effect that was abrogated by anti-CD8 antibody-mediated depletion in vivo. Because, clinically, AML vaccines are administered as postremission therapy, we established a novel model in which mice with high leukemic burdens were treated with cytotoxic therapy to induce remission (<5% marrow blasts). Postremission vaccination with 32Dp210-IL-15/IL-15R?/CD80 achieved 50% overall survival in these mice, whereas all unvaccinated mice achieving remission subsequently relapsed. These studies demonstrate that combined expression of IL-15/IL-15R? and CD80 by syngeneic AML vaccines stimulates effective and long-lasting antileukemic immunity.

Dataset Information

Human Langerhans cells use an IL-15R-?/IL-15/pSTAT5-dependent mechanism to break T-cell tolerance against the self-differentiation tumor antigen WT1.

Publications

Human Langerhans cells use an IL-15R-α/IL-15/pSTAT5-dependent mechanism to break T-cell tolerance against the self-differentiation tumor antigen WT1.

Similar Datasets

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