【作者】 席泓；

【导师】 张学光；

【作者基本信息】 苏州大学 ， 免疫学， 2006， 博士

【摘要】 SCID小鼠即重症联合免疫缺陷综合症(Severe Combined Immune deficient disease)小鼠，美国学者Bosma 1983年首先发现于C．B-17近交系小鼠，是位于16染色体的单个隐性突变基因所导致。SCID小鼠的所有T和B淋巴细胞功能测试均为阴性，对外源性抗原无细胞免疫及体液免疫应答，体内缺乏携带前B细胞、B细胞和T细胞表面标志的细胞。但是，其非淋巴性造血细胞分化不受突变基因影响，小鼠体内的淋巴细胞发育的微环境正常，仍可提供外来淋巴细胞分化所需要的必要条件。 机体抗肿瘤免疫应答主要由细胞免疫介导，而细胞免疫应答的启动则需要APC将抗原递呈给T细胞，使其活化并进行克隆性扩增。DC是体内功能最强大的APC，同时也是初次免疫应答的始动者。虽然有研究表明，DC具有非特异性免疫效应功能，能杀伤多种培养或新鲜分离的肿瘤细胞，但是，在人和动物模型中已经证实，由T细胞介导的特异性免疫应答在机体抗肿瘤中起着主导作用。因此，以DC为基础的肿瘤免疫治疗显示出良好的应用前景。 CD40是一种Ⅱ型跨膜糖蛋白，属于肿瘤坏死因子(TNF tumor necrosis factor)受体超家族。CD40还广泛表达于恶性B细胞，并且在不同来源的恶性B细胞介导不同的信号转导，发挥不同的生物学效应。本所研制的激发型CD40单克隆抗体5c11可以抑制B细胞淋巴瘤细胞株Daudi增殖，提高对凋亡的敏感性，提示有潜在的临床应用价值。已有研究证实：CD40激发后的DC可以不需要CD4~+T细胞的辅助，直接活化CD8~+细胞毒性T细胞，提示CD8~+T细胞可能通过DC表面CD40及其它分子所介导的信号而活化。恶性肿瘤患者在肿瘤发生的同时常伴有免疫系统功能的抑制，患者体内效应T细胞的数量和功能均明显低于正常人。在体外诱导足够数量的肿瘤特异性CTL回输给患者，可以部分纠正患者免疫系统的功能抑制从而对肿瘤发挥有效的治疗作用。 PD-L1属于B7超家族，肺癌、肝癌、乳腺癌、鳞状细胞癌及卵巢癌上均有PD-L1表达，是PD-1的受体，通过与CD28家族PD-1的IgV样结构域相互结合，将所产生的信号传至PD-1胞浆区尾部的ITIM基序，在免疫应答中，对T、B淋巴细胞及非淋巴组织发挥重要的负性调控作用。最近有文献证明PD-L1存在第二受体，在机更多还原

【Abstract】 The SCID mouse is of particular interest because of the absence of mature and functional T and B lymphocytes. Thus, SCID mice can tolerate a graft with human cells and particularly those of purified peripheral blood mononuclear cells (PBMC) administered by intraperitoneal injection. The reconstituted SCID mice, which are also called humanized SCID (hu-SCID) mice, provide an optimal model for studying tumor immunotherapy in an in vivo animal system.Dendritic cells(DCs) play a critical role in the initiation of immune responses, and it makes them an attractive addition to cancer vaccine strategies. CD40, a member of TNFR superfamily, is a type I membrane glycoprotein, 5C11 is an agonist CD40 monoclonal antibody prepared in our department. When B lymphoma cell line Daudi is treated with 5C11 its biological behavior is changed, and proliferation inhibition occurred, cell cycle arrested, and the sensitivity to apoptosis enhanced. Experimental results indicated the significant therapeutic potential of 5C11. PD-L1 (B7-H1), a new member of the B7 family, could also inhibit T cell proliferation. Recently studies showed that blockage of PDL1-PD1 interaction could enhance anti-tumor response in vivo.In this study we focused on establishing hu-SCID mice B lymphoma model and breast cancer models to study the therapeutic effects of DC vaccines.1. Establishment and identification of hu-SCID mice modelHu-SCID was established after treated with CTX to inhibit the hemocytopoiesis. With successive 4-day intraperitoneal injection, human peripheral blood mononuclear cells (PBMC) were engrafted into SCID mice. After engraftment, in week 4, 8 and 12 a peripheral blood, spleen and liver tissues were harvested. Further analysis consists of the following 4 parts. 1) Human CD3~+, CD19~+ cells first detected in peripheral blood with inflorescence microscope; 2) The percentage of human CD3~+, CD19~+ cells in peripheral更多还原