Immunotherapy for childhood leukemia and solid tumors using dendritic cells

(1)白血病细胞来源的树突状细胞(DCs)的产生：为了建立有效的DC免疫治疗，直接从白血病细胞中获得DCs。当原代白血病细胞在GM-CSF、TNF-α、Flt-3配体和IL-4的共同作用下培养时，AML M4和M5A患者的原始白血病细胞表达CD11c、CD80、CD83、CD86。这些结果提示AML某些亚型的白血病细胞可以分化为DC，并可能将白血病特异性抗原直接递送给T淋巴细胞。(2)DC中细胞因子相关基因的表达：比较了脐带血和成人外周血来源的DC中细胞因子相关基因的表达。在两种成熟状态下，UCB-DC的Th1反应相关基因和趋化因子基因的表达均显著低于APB-DC。推测可诱导免疫耐受的钙化颗粒蛋白A和B在脐带血DC中高表达。UCB-DC和APB-DC在免疫应答相关基因的表达上存在显著差异，这可能是导致新生儿和成人DC免疫功能差异的原因。(3)重组仙台病毒(RSeV)在儿童癌症DC介导免疫治疗中的作用；未成熟DC体外感染rSeV可诱导其自发成熟和激活。我们试图将这一结果应用于儿童癌症患者的治疗，以建立一种新的强大的DC介导的免疫疗法。分离肿瘤患儿外周血单个核细胞，在含10%自体血清、GM-CSF、IL-4和肿瘤坏死因子-α的条件下培养DC。培养的DC感染rSeV后，CD80、CD83和CD86的表达明显增强。这些发现表明，rSeV可能是DC介导的癌症免疫治疗的有力助推器，可能会改善儿童癌症患者的预后。

(1)Generation of leukemia cell-derived dendritic cells (DCs): In order to establish the effective immunotherapy using DCs, DCs were generated directly from leukemia cells. When primary leukemia blasts were cultured in the presence of GM-CSF, TNF- a , Flt-3 ligand, and IL-4, the blasts from the patients with AML M4 and M5a expressed CD 11c, CD80, CD83, CD86. These findings suggested that the leukemia cells of some AML subtypes can differentiate into DCs and might present leukemia-specific antigens directly to T lymphocytes.(2) Expression of cytokine-associated genes in DCs: The expression of cytokine-associated genes in DCs derived from umbilical cord blood (UCB) and adult peripheral blood (APB) was compared. The expression of the Th1 response-related genes and chemokine genes was significantly lower in UCB-DCs than in APB-DC in both maturation states. Calgranulins A and B, which are speculated to induce immune tolerance, showed higher expression in UCB-DCs. The expression of particular genes related to immune responses was significantly different between UCB-and APB-DCs, which may cause functional difference in DC-mediated immunity between newborns and adults.(3)The utility of recombinant Sendai virus(rSeV) for effective DC-mediated immunotherapy against childhood cancer; The ex vivo infection of immature DCs with rSeV induces their spontaneous maturation and activation. We tried to apply this result to the treatment for patients with childhood cancer to setablish a new powerful DC-mediated immunotherapy. Peripheral blood mononuclear cells were isolated from the children with cancer and were cultured in the presence 10% autologous serum, GM-CSF, IL-4 and TNF-α to generate DCs. When the generated DCs were infected with rSeV, the expression of CD80, CD83 and CD86 was markedly enhanced. These findings suggested that rSeV could be a powerful booster for DC-mediated cancer immunotherapy, which might improve the prognosis of children with cancer.