以分泌型PD-1阻断PD-1/PD-L信号通路提高SIV辅助调控蛋白免疫原性的研究

我们发现SIV辅助调控蛋白与结构蛋白联用作为疫苗抗原能够诱发广谱且均衡的免疫反应，但是辅助调控蛋白的免疫原性相对较低，尤其在与结构蛋白联用时更低。如何有效提高辅助调控蛋白的免疫原性是亟待解决的科学问题。利用携带分泌型PD-1（sPD-1）基因的腺病毒载体，我们已在小鼠模型上证实，以sPD-1竞争性阻断PD-1介导的免疫负调节信号通路后，Gag抗原可引发更强的细胞免疫反应。我们拟进一步采用该策略来提高辅助调控蛋白的免疫原性。我们将设计并构建一系列以不同方式携带sPD-1基因的腺病毒载体，在小鼠模型上筛选最能有效提高辅助调控蛋白免疫原性的策略；同时，我们将利用纯化的sPD-1蛋白，在小鼠脾淋巴细胞中研究信号通路阻断的免疫学效应，尤其是对抗原特异性T淋巴细胞增殖能力及细胞因子分泌能力的影响,从而揭示PD-1信号通路阻断提高抗原免疫原性的机制。本研究的结果将对于新型艾滋疫苗的设计有重要的参考价值。

We have found that co-vaccination of SIV regulatory and accessory proteins with SIV structural proteins induced broad-spectrum and balanced immune response. The immunogenecity of regulatory and accessory proteins, however, was relatively low, especially when co-vaccinated with the structural proteins. Thereby, how to effectively improve their immunogenecity is an important and urgent scientific problem to be settled. Our previous results demonstrated that blocking the PD-1/PD-L inhibitory signaling pathway by using secreted PD-1 (sPD-1) harbored in a recombinant adenovirus vector (rAdV) significantly enhanced the capacity of SIV Gag to induce cellular immune response. In this project, we aim to advance our study to enhance the immunogenecity of SIV regulatory and accessory proteins through blockade of PD-1 signalling pathway with sPD-1. We have generated a series of rAdVs carrying different forms of sPD-1 expression cassette, and expect to select the most effective blockade strategy that can improve the immunogenecity of SIV regulatory and accessory proteins in the available mouse model. Meanwhile, the impact of PD-1 signaling pathway blockade on the capacity of antigen-specific T-cell proliferation and cytokine secretion will be addressed in vitro using mouse lymphocytes isolated from spleen, which will dissect the mechanism how PD-1 signaling pathway blockade can improve antigen immunogenicity. This study will provide important guidance for designing new HIV/SIV vaccine.