In Vivo Targeted Vaccines for Tumor Immunotherapy

描述（由申请人提供）：由于树突状细胞（DC）对诱导T细胞介导的免疫具有卓越的责任，因此在癌症背景下疫苗体内靶向DC直观上是显而易见的。热休克蛋白70（hsp 70）与DC上的抗原（Ag）摄取和信号传导受体结合，并且可以作为能够提高疫苗效力的DC靶向分子。淋巴组织中活化的载银DC的寿命也是与特异性免疫诱导密切相关的重要问题。延长载银DC在体内的存活可能增强DNA疫苗的效力。我们最近已经证明，融合蛋白组成的肿瘤抗原和热休克蛋白70（Aghsp 70），编码的DNA疫苗诱导显着的抗肿瘤免疫。此外，这些疫苗的功效通过经由“存活基因”Bcl-xl的递送延长DC存活而增强。我们假设：1）Aghsp 70在体内靶向DC刺激DC活化并诱导T细胞介导的免疫，和2）携带Aghsp 70的DC存活的延长极大地改善了Ag特异性T细胞应答的幅度和质量，导致有效的临床益处。具体目标1：测试OVAhsp 70蛋白是否通过组合的TLR 4/CD 40触发激活DC，并通过CD 91/CD 40/LOX-1受体介导的Ag摄取增强DC Ag呈递能力，导致诱导有效的OVA特异性T细胞应答;具体目标2：测试是否可以通过DNA疫苗接种导致的携带OVAhsp 70的DC存活的体内延长来诱导强烈和持续的OVA特异性T细胞应答;具体目标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.