In Vivo Targeted Vaccines for Tumor Immunotherapy

由于树突状细胞(DC)在诱导T细胞介导的免疫方面具有突出的责任， 在癌症的背景下，将疫苗靶向体内的DC是直观的。热休克蛋白 热休克蛋白70(HSP70)与树突状细胞表面抗原(Ag)摄取和信号受体结合，可作为树突状细胞 靶向分子能够提高疫苗的效力。活性银轴承的寿命研究 淋巴组织中的DC也是与诱导特异性免疫密切相关的一个重要问题。 延长体内载银DC的存活时间可能会增强DNA疫苗的效力。我们有 最近证实，由肿瘤抗原和热休克蛋白70组成的融合蛋白(AghspTO)编码 在DNA疫苗方面，可诱导显著的抗肿瘤免疫。此外，这些疫苗的效力 通过转导“生存基因”Bc l-xl延长DC存活时间。我们 假设：1)AghspTO体内靶向DC刺激DC激活并诱导T细胞- 2)携带Aghsp70的DC存活时间的延长大大改善了 Ag特异性T细胞反应的大小和质量，从而产生潜在的临床益处。为了测试这一点 假设，我们将追求三个具体目标： 特定目的1：检测OVAhsp70蛋白是否通过结合TLR4/CD40激活DC 并通过CD91/CD40/LOX-1受体介导的抗原摄取增强DC的抗原提呈能力 在诱导强大的卵清蛋白特异性T细胞反应中； 特定目标2：测试是否可以诱导强烈和持续的OVA特异性T细胞反应 DNA疫苗可延长体内携带OVAhsp70的DC存活时间； 具体目的3：评价体内靶向疫苗诱导的抗肿瘤免疫效果。 从这些研究中获得的实验结果将有助于优化未来的肿瘤 疫苗设计并提供对DC免疫生物学的更多洞察力。

As dendritic cells (DCs) have pre-eminent responsibility for inducing T cell-mediated immunity, the targeting of vaccines to DCs in vivo is intuitively obvious in the setting of cancer. Heat shock protein hsp70 (hsp70) binds to both antigen (Ag)-uptake and signalingreceptors on DCs and may serve as a DC targeting molecule capable of improving the efficacy of vaccines. The longevity of activated Ag-bearing DCs in lymphoid tissues is also an important issue germane to the induction of specific immunity. Prolonging Ag-bearing DC survival in vivo may potentiate the potency of DNA vaccines. We have recently demonstrated that fusion proteins composed of tumor Ag and hsp70 (AghspTO) that are encoded in DNA vaccines induce significant anti-tumor immunity. Furthermore, the efficacy of these vaccines was augmented by prolonging DC survival via the delivery of the 'survival gene' Bcl-xl. We hypothesize that: 1) the in vivo targeting of AghspTO to DCs stimulates DC activation and induces T cell- mediated immunity and 2) that the prolongation of Aghsp70-bearing DC survival greatly improves the magnitude and quality of Ag-specific-T cell responses, resulting in potent clinical benefit. To test this hypothesis, we will pursue three specific aims: Specific Aim 1: Test whether OVAhsp70 proteins activate DCs via combined TLR4/CD40 triggering and enhance DC Ag-presenting capacity via CD91/CD40/LOX-1 receptor-mediated Ag-uptake, resulting in the induction of potent OVA-specific-T cell responses; Specific Aim 2: Test whether strong and sustained OVA-specific-T cell responses can be induced by the in vivo prolongation of OVAhsp70-bearing DC survival resulting from DNA vaccination; Specific Aim 3: Evaluate the efficacy of anti-tumor immunity induced by the In Vivo Targeted Vaccines. Experimental results obtained from these studies will be important in helping to optimize future tumor vaccine designs and provide additional insight into DC immunobiology.