Cellular Immune Responses Induced by SIVdelta-vif plus IL-15 DNA Vaccine

描述(由申请人提供)：迫切需要开发一种有效和安全的人类免疫缺陷病毒(HIV)疫苗，主要目标是阻止艾滋病流行的传播。通过阐明疫苗诱导保护的免疫相关因素，将有助于此类有效疫苗的设计。我们在恒河猴身上进行了疫苗接种研究，以评估含有vif缺失的SIVmac239前病毒(SIVvif前病毒)的质粒DNA作为前DNA疫苗的作用。此外，我们还研究了恒河猴白介素15表达载体与SIV？VIF前病毒DNA共接种时的佐剂活性。这些研究结果表明，与IL-15表达载体联合免疫对SIV vif缺失的前病毒DNA疫苗具有显著的佐剂作用，并增强了对致病SIVmac251的阴道攻击的保护作用。此外，用干扰素检测SIV特异性细胞免疫应答。ELISPOT和T细胞增殖试验显示干扰素-？ELISPOT通过将IL-15作为前病毒DNA疫苗的佐剂进行应答。这些由NIH资助的疫苗研究现已结束。我们建议使用10色多参数流式细胞术进一步检测来自相同疫苗研究的冷冻保存的PBMC样本的病毒特异性细胞免疫反应。这项检测将评估SIV诱导的T细胞细胞内细胞因子的表达，包括干扰素-α、肿瘤坏死因子-α和白介素2，并检测细胞毒性T细胞脱颗粒(CD107a)、CD8T细胞记忆发育(CD127或IL-7受体a)和阴性免疫调节蛋白(程序死亡1/PD-1)的特异性细胞表面标志的表达。这种类型的免疫反应评估在资助这些SIV？VIF DNA疫苗研究的NIH原始提案中没有描述。然而，这些研究的观察结果以及最近的报告表明，这些功能谱对阐明对疫苗设计至关重要的免疫相关是有用的，这一调查现在得到了很好的证明。我们的假设是，应用新的工具对SIV-VIF前病毒DNA免疫猕猴进行全面的免疫反应分析，无论有没有IL-15表达载体，都将阐明IL-15佐剂活性和疫苗诱导的病毒载量控制的免疫相关性(S)。此外，IL-15已被认为是HAART患者的一种潜在的免疫疗法。因此，仔细阐明与潜在有效的细胞因子佐剂(如IL-15)相关的细胞免疫反应可能会影响未来HIV-1疫苗和疗法的设计。公共卫生相关性：最近在猴子动物模型中的研究结果表明，在高度减毒的SIV-VIF DNA疫苗中加入一种名为IL-15的淋巴细胞生长因子，可以提高该疫苗的有效性。然而，疫苗诱导的免疫反应的标准测试并没有确定IL-15改进疫苗的具体原因或机制。我们建议使用过去十年发展的新技术进一步检查病毒特异性的细胞免疫反应，以确定IL-15改进DNA疫苗的机制。这些研究的结果随后可能被用于未来设计更有效的HIV-1疫苗，以及设计HIV-1感染的免疫疗法。

DESCRIPTION (provided by applicant): The need is pressing to develop an effective and safe vaccine against the human immunodeficiency virus (HIV) with the primary objective of arresting the spread of the AIDS epidemic. Design of such efficacious vaccines will be facilitated by the elucidation of immune correlates of vaccine-induced protection. We have conducted vaccination studies in rhesus macaques to evaluate a plasmid DNA containing a vif-deleted SIVmac239 provirus (SIVvif provirus) as a proviral DNA vaccine. Furthermore we investigated the adjuvant activity of a rhesus macaque interleukin (IL)-15 expression plasmid when co-inoculated with the SIV?vif proviral DNA. Findings from these studies indicated that co-immunization with an IL-15 plasmid expression vector affords a significant adjuvant effect to the SIV vif-deleted proviral DNA vaccine and enhanced protection against vaginal challenge with pathogenic SIVmac251. Furthermore, examination of SIV-specific cellular immune responses by interferon-? ELISpot and T cell proliferation assays revealed a significant enhancement of interferon-? ELISpot responses by inclusion of IL-15 as an adjuvant for the proviral DNA vaccine. These NIH-funded vaccine studies have now been concluded. We propose to further examine virus-specific cellular immune responses from cryopreserved PBMC samples banked from these same vaccine studies, using a 10 color multi-parameter flow cytometric assay. This assay will evaluate SIV-induced T cell intracellular expression of cytokines including interferon-?, tumor necrosis factor (TNF)-a, and interleukin-2 and also test for expression of specific cell surface markers for cytotoxic T cell degranulation (CD107a), CD8 T cell memory development (CD127 or IL-7 receptor a) and a negative immunoregulatory protein (program death 1/PD-1). This type of immune response assessment was not described in the original NIH proposal that funded these SIV?vif DNA vaccine studies. However, this investigation is now well justified by observations from these studies and by recent reports showing the utility of these functional profiles to elucidate immune correlates that are critical for vaccine design. The hypothesis is that implementation of novel tools for comprehensive immune response analysis in macaques vaccinated with SIV?vif proviral DNA with or without IL-15 expression plasmid, will elucidate an immune correlate(s) for IL-15 adjuvant activity and vaccine-induced control of virus load. Furthermore, Il-15 has been considered as a potential immunotherapeutic for patients on HAART. Accordingly, careful elucidation of cellular immune responses associated with a potentially effective cytokine adjuvant such as IL-15 may impact design of future HIV-1 vaccines and therapeutics. PUBLIC HEALTH RELEVANCE: Findings from recent studies in monkey animal models, suggested that including a lymphocyte growth factor designated interleukin (IL)-15, as part of the highly attenuated SIV?vif DNA vaccine, improved the effectiveness of this vaccine. However standard tests for vaccine-induced immune responses did not identify a specific cause or mechanism by which IL-15 improved the vaccine. We propose to further examine virus-specific cellular immune responses using new technologies developed over the past decade, to identify mechanisms by which IL-15 improved this DNA vaccine. Findings from these studies may then be used for future design for more effective HIV-1 vaccines, as well as design for immunotherapeutics for HIV-1 infection.