EIAV vector targeting dendritic cells to induce CTL

描述(由申请人提供)：针对慢病毒的免疫保护的最终相关性尚未定义；尽管CTL是一个关键组成部分。这一结论是基于慢病毒感染中病毒血症的控制和CTL的出现之间的时间关联，以及CTL和低HIV-1负荷之间的其他关联。此外，在病毒水平得到控制的SIV感染猴子中，CD8+细胞的耗尽会导致病毒血症，而在急性感染期间这些细胞的耗尽会导致无法控制最初的病毒血症。尽管在任何HIV-1预防性疫苗中都需要CTL，但在具有不同MHC I类分子的个体群体中，如何诱导所需数量的CTL记忆细胞针对多种蛋白质上的表位存在知识缺口。 在感染马传染性贫血病毒(EIAV)的马中，CTL与控制原发病毒血症有关，后来在携带马的马中，CTL与控制原发病毒血症有关。CTL是针对EIAV Gag、Pol、Env、Rev和调节蛋白S2的表位，目的是在幼马体内诱导CTL。在不同单倍型的马身上，最佳的结果是对多种EIAV蛋白上的表位进行CTL，一种策略是用慢病毒载体靶向树突状细胞，该载体产生进入MHC I类加工途径的EIAV蛋白。最近的初步数据表明，EIAV除了感染巨噬细胞和内皮细胞外，还感染树突状细胞。因此，计划使用EIAV载体在幼马体内诱导CTL，利用EIAV Env靶向初级免疫反应所需的树突状细胞，并靶向其他抗原提呈细胞(APC)。EIAV载体可以在转导的APC中表达Gag、Pol和Tat蛋白，但不能表达Env。这是因为载体包膜的包装细胞中产生的Env蛋白来自RNA，缺乏包装信号来帮助确保载体转导的细胞不会产生传染性病毒。尽管慢病毒载体在人类中的使用存在安全性问题，但以树突状细胞为靶点的EIAV载体有效地诱导马对EIAV蛋白的CTL将是一个新的观察结果，并将刺激针对人APC的其他类型载体的进一步研究。因此，这一提议将检验这样一个假设，即在体内用EIAV载体靶向树突状细胞将诱导马的CTL对多种病毒蛋白产生作用。

DESCRIPTION (provided by applicant): The definitive correlates for immune protection against lentiviruses have not yet been defined; although CTL are one critical component. This conclusion is based on the temporal association between viremia control in lentiviral infections and the appearance of CTL, and on other correlations between CTL and low HIV-1 loads. Further, depletion of CD8+ cells in SIV-infected monkeys with controlled virus levels results in viremia, and depletion of these cells during acute infection results in a failure to control the initial viremia. Despite the need for CTL in any preventive vaccine for HIV-1, there is a gap in knowledge about how to induce requisite numbers of CTL memory cells to epitopes on multiple proteins in populations of individuals with disparate MHC class I molecules. CTL are associated with control of primary viremia in equine infectious anemia virus (EIAV)-infected horses, and later, in carrier horses. CTL occur to epitopes on EIAV Gag, Pol, Env, Rev, and regulatory protein S2, and the goal is to induce CTL in naive horses. Optimal results would be CTL to epitopes on multiple EIAV proteins in horses with diverse haplotypes and one strategy is to target dendritic cells with a lentivirus vector that produces EIAV proteins which enter the MHC class I processing pathway. Recent preliminary data demonstrate that EIAV infects dendritic cells in addition to known infection of macrophages and endothelial cells. Therefore, the plan is to use an EIAV vector to induce CTL in naive horses which will use EIAV Env to target dendritic cells required for a primary immune response and also to target other antigen presenting cells (APC). The EIAV vector is designed to express Gag, Pol and Tat proteins in transduced APC, but not Env. This is because the Env protein made in the packaging cells for vector envelope is from RNA lacking a packaging signal to help assure that vector-transduced cells will not produce infectious virus. Even though there are safety concerns with lentivirus vector use in humans, effective induction of CTL in horses to EIAV proteins with an EIAV vector targeting dendritic cells would be a novel observation and would stimulate further research on other types of vectors to target human APC. Thus, this proposal will test the hypothesis that targeting dendritic cells in vivo with an EIAV vector will induce CTL in horses to multiple viral proteins.