Immune Responses to CMV DNA Vaccination

描述(申请人提供)：加州圣地亚哥的Vical公司正在开发一种双价CMV DNA疫苗，用于预防CMV疾病及其在移植中的后果。VCL-CBO 1疫苗包含两个质粒，一个编码主要表面蛋白gB，另一个编码被膜蛋白pp65，由泊洛沙姆CRL1005配制，以增加T细胞和B细胞反应的诱导。对自然CMV感染的免疫反应已被用作测量CIM和CD8 T细胞的模型，但这些检测方法是否可作为CMV疫苗试验中免疫的替代标记物还没有得到充分的研究。这项超级加速奖申请的目的将是使用在Vical第一阶段和第二阶段试验中收集的血液样本来开发适当的GLP分析，可用于监测CMV血清阳性和CMV血清阴性受试者的疫苗反应，并建立免疫学反应与临床和病毒学结果的相关性。 其具体目的将是：1)使用基于多肽的ELISPOT技术和细胞内细胞因子细胞仪(ICC)方法来确定VCL-CB01诱导T细胞反应的水平，并将这两种方法相互比较，并与传统的淋巴增殖试验进行比较。我们将通过纵向测量疫苗编码的抗原pp65和疫苗中未包括的另一种CMV抗原(IE1)的反应来区分CMV T细胞反应的自然波动和CMV血清阳性者的疫苗诱导反应。2)通过多参数流式细胞术、MHC I类四聚体结合研究以及将pp65表位映射到15-MERS的水平，在血清阴性和血清阳性的受试者中比较和对比DNA疫苗诱导的T细胞应答和自然感染引起的T细胞应答。3)研究和开发检测CMV中和抗体的新方法。 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的系统中进行了研究。我们将发现接种疫苗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。我们将在强大的自然免疫力的背景下研究疫苗接种的免疫反应，这可能在治疗性疫苗领域具有重要意义。我们将部分确定DNA疫苗诱导的T细胞的记忆和效应表型，并能够在未来将这些表型与其他病原体自然感染或其他疫苗接种方式诱导的表型进行比较。最后，我们将进一步研究巨细胞病毒中和的测量领域，这在母婴疾病预防和可能的普遍疫苗接种领域将是至关重要的。

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.