Immune Responses to CMV DNA Vaccination

描述（由申请人提供）：Vical Incorporated of San Diego，CA正在开发用于预防CMV疾病及其在移植中的后果的二价CMV DNA疫苗。疫苗VCL-CBO 1含有两种质粒，一种编码主要表面蛋白g B，另一种编码被膜蛋白pp 65，并配制在泊洛沙姆CRL 1005中以增加T细胞和B细胞应答的诱导。对天然CMV感染的免疫应答已被用作测量CIM+和CD 8 T细胞的模型，但这些测定是否可用作CMV疫苗试验中的免疫替代标志物尚未得到充分研究。本超加速奖申请的目的是使用Vical I期和II期试验期间采集的血液样本开发适当的GLP试验，可用于监测CMV血清阳性和CMV血清阴性受试者的疫苗应答，并开发免疫应答与临床和病毒学结局的相关性。 具体目标是：1）使用基于肽的ELISPOT技术和细胞内细胞因子细胞计数（ICC）方法，确定VCL-CB 01诱导的T细胞应答的诱导水平，将两种方法相互比较并与常规淋巴细胞增殖试验进行比较。我们将通过纵向测量对疫苗编码抗原pp 65和疫苗中不包括的另一种CMV抗原（IE 1）的应答，区分CMV T细胞应答的自然波动和CMV血清阳性中疫苗诱导的应答。2)通过使用多参数流式细胞术、MHC I类四聚体结合研究和pp 65表位与这些试验中使用的15聚体水平的映射，比较和对比DNA疫苗诱导的T细胞应答与血清阴性和血清阳性受试者中自然感染引起的应答。3)研究和开发新的方法来测量CMV中和抗体。 这些研究将在许多方面对该领域具有重要意义。首先，我们将建立疫苗接种和对自然感染的反应之间的关系，这些关系已经在有限数量的系统中进行了研究。我们将发现对疫苗接种的免疫显性反应是否与自然感染诱导的免疫显性反应相似。我们将研究在有效的自然免疫环境中对疫苗接种的免疫应答，这在治疗性疫苗领域可能是重要的。我们将部分确定DNA疫苗接种诱导的T细胞的记忆和效应表型，并能够将这些表型与其他病原体或其他疫苗接种方式自然感染诱导的表型进行比较。最后，我们将进一步测量CMV中和的领域，这将在母胎疾病预防和可能的普遍疫苗接种领域至关重要。

DESCRIPTION (provided by applicant): Vical Incorporated of San Diego, CA is developing a bivalent CMV DNA vaccine for use in prevention of CMV disease and its consequences in transplantation. The vaccine, VCL-CBO 1, contains two plasmids, one encoding the major surface protein gB, and the other encoding the tegument protein pp65, and is formulated in the poloxamer CRL1005 to increase the induction of T cell and B cell responses. Immune responses to natural CMV infection have been used a model for the measurement of CIM" and CD8 T cells, but whether these assays will be applicable as surrogate markers of immunity in CMV vaccine trials has not been fully investigated. The objective of this Hyperaccelerated Award application will be to use the blood samples collected during the Vical Phase 1 and Phase 2 Trials to develop appropriate GLP assays that can be used to monitor vaccine responses in both CMV seropositive and CMV seronegative subjects, and to develop correlates of immunologic response with clinical and virologic outcomes. The specific AIMS will be to: 1) Determine the level of induction of T cell responses induced by VCL-CB01 using a peptide-based ELISPOT technique and intracellular cytokine cytometry (ICC) method, comparing the two methods to each other and to conventional lymphoproliferative assays. We will differentiate between the natural fluctuations in the CMV T-cell response and vaccine induced responses in CMV seropositives by longitudinal measurement of responses to the vaccine-encoded antigen, pp65, and another CMV antigen not included in the vaccine (IE1). 2) Compare and contrast DNA-vaccine induced T cell responses with those resulting from natural infection in seronegative and seropositive subjects through the use of multiparameter flow cytometry, MHC Class I tetramer binding studies and mapping of pp65 epitopes to the level of the 15-mers used in these assays. 3) Examine and develop novel methods for the measurement of neutralizing antibodies to CMV. These studies will be significant to the field in many ways. First, we will establish a relationship between vaccination and responses to natural infection that have been studied in a limited number of systems. We will discover whether the immunodominant responses to vaccination are similar to those induced by natural infection. We will study the immune responses to vaccination in the setting of potent natural immunity, which may be important in the area of therapeutic vaccines. We will determine in part the memory and effector phenotype of the T cells induced by DNA vaccination, and be able to compare these phenotypes to those induced by natural infection by other pathogens or by other vaccination modalities in the future. Lastly, we will further the field of measurement of CMV neutralization, which will be critical in the area of maternal-fetal disease prevention and possible universal vaccination.