In Vivo Targeted Vaccines for Tumor Immunotherapy

由于树突状细胞（DC）具有诱导T细胞介导的免疫的突出责任， 在癌症的情况下，疫苗体内靶向DC直观上是显而易见的。热休克蛋白 热休克蛋白70（hsp70）与DC上的抗原（Ag）摄取受体和信号受体结合，可作为DC 能够提高疫苗效力的靶向分子。活化载银的寿命 淋巴组织中的DC也是与诱导特异性免疫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。我们有 最近证明，由肿瘤Ag和hsp70（AghspTO）组成的融合蛋白编码， 在DNA疫苗中诱导显著抗肿瘤免疫。此外，这些疫苗的有效性 通过递送"存活基因" Bcl-xl延长DC存活来增强。我们 假设：1）AghspTO体内靶向DC刺激DC活化并诱导T细胞- 2）携带Aghsp70的DC存活时间的延长大大改善了免疫功能。 Ag特异性T细胞应答的幅度和质量，导致有效的临床益处。为了验证这一 假设，我们将追求三个具体目标： 具体目的1：测试OVAhsp70蛋白是否通过组合的TLR4/CD40触发激活DC 并通过CD91/CD40/LOX-1受体介导的Ag摄取增强DC Ag呈递能力， 诱导有效的OVA特异性T细胞应答; 具体目标2：测试是否可以通过免疫调节剂诱导强烈和持续的OVA特异性T细胞应答。 DNA疫苗接种导致的携带OVAhsp70的DC存活的体内延长; 具体目标3：评价体内靶向疫苗诱导的抗肿瘤免疫效力。 这些研究获得的实验结果对于帮助优化未来的肿瘤非常重要 疫苗设计和提供更多的洞察DC免疫生物学。

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.