PROLIFERATIVE CONDITIONING OF TUMOR-COMPETENT DENDRITIC CELL PRECURSORS

描述（由申请人提供）：树突状细胞（DC）可以确定是否有强大的细胞介导的免疫力构成对抗原攻击的适当反应。干细胞动员治疗可用于在整个荷瘤宿主中增殖和分布DC前体，但也观察到FltSL+GMCSF等动员治疗可促进免疫抑制并有利于肿瘤进展。我们最近发现，用FK 3L + IL 6调节小鼠骨髓（BM）是DC动员的一种非常有前途的策略。Flt 3L + IL 6可诱导CD 34阳性干细胞大量增殖，与FltSL + GMCSF相比，FltSL + GMCSF具有以下作用：（1）FltSI+ILG预处理可抑制正常的多系造血，促进DC的分化;（2）Flt 3L + IL 6可促进对TLR激动剂的反应性，促进DC 1型分化和IL-12 p70的分泌;（3）它允许自发的DC成熟，绕过对信号如CD 40配体或toll样受体（TLR）激动剂的正常需求;（4）它赋予对肿瘤相关免疫抑制剂如IL-10、TGF-β 1、TGF-β 2、TGF-β 3、TGF-β 4、TGF-β 1、TGF-β 2、TGF-β 1、（3）VEGF和PGE 2;（5）它诱导对肿瘤接触本身的响应能力，加速DC 1极化，包括IL-12产生。由于这些特殊的性质，暴露于活肿瘤细胞的Flt 3 L + IL 6调节的DC还显示出逆转耐受性和促进治疗有效的肿瘤特异性T细胞增殖的上级能力。重要的是，如果在增殖调节期间也存在GM-CSF，则Flt 3L + IL 6 DC调节的这些有利影响被完全消除。该项目的目标是：（1）表征使FU 3L + IL 6条件化的小鼠DC在治疗上具有上级优势的机制，从而可以在人DC中引发相同的性质;（2）表征和优化Flt 3L + IL 6动员在荷瘤小鼠中的治疗作用，将rIL 6与有效的设计细胞因子hyperlLG进行正式比较;（3）比较Flt 3L + IL 6与FltSL+GMCSF增殖条件下人单核细胞来源的DC与人CD 34 pos BM细胞的功能，包括TLR表达。概述：树突状细胞（DC）是人体最好的细胞，用于教育免疫系统识别和摧毁癌症。我们已经鉴定了一种特定的治疗，FltSL加IL 6，导致DC的上级活化，我们希望这将提供一种更有效的抗癌治疗。该项目旨在提供将这项研究用于治疗癌症患者的临床试验所需的信息。

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.