In Vivo Targeted Vaccines for Tumor Immunotherapy

描述（由申请人提供）：由于树突状细胞（dc）在诱导T细胞介导的免疫方面具有卓越的作用，因此在癌症的背景下，疫苗对体内树突状细胞的靶向是直观明显的。热休克蛋白hsp70 （hsp70）与DC上的抗原（Ag）摄取和信号受体结合，可能作为DC靶向分子，能够提高疫苗的效力。淋巴组织中活化的含银树突状细胞的寿命也是与特异性免疫诱导相关的一个重要问题。延长含银DC在体内的存活时间可能会增强DNA疫苗的效力。我们最近证明了DNA疫苗中编码的由肿瘤Ag和hsp70 （Aghsp70）组成的融合蛋白可诱导显著的抗肿瘤免疫。此外，这些疫苗的功效通过传递“存活基因”Bcl-xl而延长DC存活。我们假设：1)Aghsp70在体内靶向DC刺激DC激活并诱导T细胞介导的免疫；2)携带Aghsp70的DC存活时间的延长大大提高了ag特异性T细胞应答的强度和质量，从而产生了强大的临床效益。为了验证这一假设，我们将寻求三个特定目标：特定目标1：测试OVAhsp70蛋白是否通过TLR4/CD40联合触发激活DC，并通过CD91/CD40/LOX-1受体介导的ag摄取增强DC的ag呈递能力，从而诱导有效的ova特异性t细胞反应；特异性目的2：测试DNA疫苗接种是否能通过体内延长携带ovahsp70的DC存活时间来诱导强烈和持续的ova特异性t细胞反应；特异性目的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，并为DC免疫生物学提供额外的见解。

DESCRIPTION (provided by applicant): 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 signaling receptors 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 (Aghsp70) 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 Aghsp70 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.