PROLIFERATIVE CONDITIONING OF TUMOR-COMPETENT DENDRITIC CELL PRECURSORS

描述（由申请人提供）：树突状细胞（dc）可以确定强大的细胞介导免疫是否构成对抗原挑战的适当反应。干细胞动员治疗可用于在整个肿瘤宿主中增殖和分布DC前体，但FltSL+GMCSF等动员治疗也被观察到可促进免疫抑制并促进肿瘤进展。我们最近发现，用FK3L+IL6调节小鼠骨髓是一种非常有前途的DC动员策略。与FltSL+GMCSF相比，Flt3L+IL6可引起CD34pos干细胞的大量增殖，但与FltSL+GMCSF相反，(1)FltSI+ILG调节抢先了正常的多系造血，有利于近全球DC分化；(2)促进对toll样受体（TLR）激动剂的均匀反应，极大地促进dc1型极化和IL-12p70的分泌；(3)它允许自发DC成熟，绕过对CD40配体或toll样受体（TLR）激动剂等信号的正常要求；(4)它对肿瘤相关的免疫抑制剂如IL-10、TGF-(3)、VEGF和PGE2具有耐药性；(5)它通过加速DC1极化诱导自身对肿瘤接触的反应能力，包括IL-12的产生。有了这些特殊的特性，暴露于活的肿瘤细胞的Flt3L+IL6条件dc也显示出卓越的能力来逆转耐受性和促进治疗有效的肿瘤特异性T细胞的增殖。重要的是，如果在增殖调节过程中也存在GM-CSF， Flt3L+IL6 DC调节的这些有利影响将被完全消除。该项目的目的是：(1)表征使FU3L+IL6条件小鼠dc具有治疗优势的机制，以便在人类dc中引发相同的特性；(2)表征和优化Flt3L+IL6动员对荷瘤小鼠的治疗作用，并将rlL6与强效设计细胞因子hyperlLG进行正式比较；(3)比较用Flt3L+IL6与FltSL+GMCSF进行增殖后，人单核细胞来源的dc与人CD34pos BM细胞的功能，包括TLR的表达。概要：树突状细胞（dc）是人体教育免疫系统识别和摧毁癌症的最佳细胞。我们已经确定了一种特殊的治疗方法，FltSL加IL6，结果是优越的DCs激活，我们希望这将提供更有效的治疗癌症。该项目旨在提供所需的信息，将这项研究用于治疗癌症患者的临床试验。

DESCRIPTION (provided by applicant): Dendritic cells (DCs) can determine whether or not robust cell-mediated immunity constitutes the appropriate response to antigenic challenge. Stem cell mobilizing treatments can be employed to proliferate and distribute DC precursors throughout the tumor-bearing host, but mobilization treatments such as FltSL+GMCSF have also been observed to promote immunosuppression and favor tumor progression. We recently identified that mouse bone marrow (BM) conditioning with FK3L+IL6 is an exceptionally promising strategy for DC mobilization. Flt3L+IL6 causes abundant proliferation of CD34pos stem cells, comparably to FltSL+GMCSF, but in contrast to FltSL+GMCSF, (1) FltSI+ILG conditioning preempts normal multilineage hematopoiesis in favor of nearly global DC differentiation; (2) it promotes uniform responsiveness to toll-like receptor (TLR) agonists, greatly facilitating DC1-type polarization and IL-12p70 secretion; (3) it licenses spontaneous DC maturation, bypassing normal requirements for signals such as CD40 ligand or toll-like receptor (TLR) agonists; (4) it confers resistance to tumor-associated immunosuppressants such as IL-10, TGF-(3, VEGF and PGE2; (5) it induces the capacity to respond to tumor contact itself with accelerated DC1 polarization, including IL-12 production. With these exceptional properties, Flt3L+IL6 conditioned DCs exposed to viable tumor cells also display a superior capacity to reverse tolerance and promote proliferation of therapeutically potent, tumor-specific T cells. Importantly, these favorable impacts of Flt3L+IL6 DC conditioning are completely abrogated if GM-CSF is also present during proliferative conditioning. This project's aims are: (1) to characterize the mechanisms which render FU3L+IL6 conditioned mouse DCs therapeutically superior, so that the same properties can be elicited in human DCs; (2) to characterize and optimize the therapeutic impacts of Flt3L+IL6 mobilization in tumor-bearing mice, with formal comparisons of rlL6 to the potent designer cytokine hyperlLG; (3) to compare the function, including TLR expression, of human monocyte-derived DCs with human CD34pos BM cells after the latter have been proliferatively conditioned with Flt3L+IL6 vs FltSL+GMCSF. Lay summary: Dendritic cells (DCs) are the body's best cell for educating the immune system to recognize and destroy cancer. We have identified that a particular treatment, FltSL plus IL6, results in superior activation of DCs, which we hope will provide a more effective treatment against cancer. This project aims to provide the information needed to bring this research to a clinical trial for treating cancer patients.