Development of Vaccine Strategies to prevent EBV+ Lymphoma in Patients with HIV

描述（由申请方提供）：感染HIV的患者发生恶性B细胞淋巴增生性疾病（LPD）的风险增加。这些LPD中的大多数对EB病毒（EBV）呈阳性，具有侵袭性的临床过程，并且与不良预后相关。EBV是一种致癌的人类疱疹病毒，感染全球90%以上的成年人，并与广泛的恶性肿瘤有关。HIV感染患者中EBV-LPD的发生率部分与EBV特异性T淋巴细胞应答的数量和/或质量不足有关。我们推测，针对EBV裂解抗原和潜伏抗原的细胞免疫缺陷导致EBV-LPD的风险增加，疫苗增强的EBV特异性免疫将恢复保护并防止该高危人群中EBV-LPD的发展。我们利用了一种SCID小鼠模型，当用来自健康EBV血清阳性供体的人白细胞移植时，该模型自发地产生人EBV-LPD。我们发现了几种EB病毒潜伏和裂解抗原识别的人CD 8（+）T细胞时，疾病在体内得到控制。此外，我们验证了这些相同抗原在具有EBV-LPD的医源性免疫抑制患者中的识别，同时在减少其免疫抑制方案后成功地在体内控制其疾病。我们将几个EBV基因克隆到腺相关和腺病毒构建体中，感染人抗原呈递细胞，并证明了强大的自体T细胞扩增。使用HLA特异性四聚体加载来自BZLF的免疫优势肽，我们记录了在这些患者中发生的BZLF 1特异性T细胞的体内扩增与EBV+肿瘤消退和改善患者生存相关。在白血病淋巴瘤协会和企业合作伙伴的支持下，我们最近完成了BZLF 1的大规模纯化，并正在为明年计划的IND前会议启动临床前毒性研究。由于一个全面的EBV疫苗可能需要多个EBV蛋白靶点，我们建议完成4个额外的靶蛋白的表征，并进行临床前分析，以确定可能在临床上进一步开发的有前途的免疫原。这项重大机会赠款将实现三个具体目标：（1）在体外表征对5种拟议全长基因产物中每一种的各种HLA类型的人类细胞反应，以确定包括在疫苗接种策略中的最佳候选基因产物;（2）评估全长纯化的病毒多肽制剂在刺激和维持EBV特异性记忆T细胞扩增和预防致命性人EBV-T细胞扩增中的功效。在我们的EBV-LPD的嵌合小鼠-人模型中检测与淋巴组织增生性病症相关的细胞因子，和（3）扩大全长候选多肽的生产，用于进一步表征、评价最佳递送和佐剂活性、毒性评价、生物标志物验证和免疫原性研究。一旦我们在这笔赠款的支持下完成了上述基本探索性研究，我们将确定在广泛的HLA谱中“看到”的最佳病毒靶点，并能够申请IND进行I期试验，以确保向具有发展EBV-LPD高风险的HIV+患者提供特定疫苗制剂的安全性。最终，这种病毒驱动的恶性肿瘤的预防方法可能会被证明是更有效，更便宜，并通过进一步降低EBV-LPD的发病率和改善感染HIV的患者的生活质量，使全球更多的人受益。 公共卫生相关性：感染人类免疫缺陷病毒（HIV）的人患恶性B细胞淋巴增生性疾病（LPD）的风险增加。这些LPD中的大多数对EB病毒（EBV-LPD）呈阳性，具有侵袭性的临床过程，并且与不良预后相关。健康的、有免疫能力的人不会发生EBV-LPD，因为他们有高效的、适应性的细胞抗原特异性免疫应答。HIV感染患者中EBV-LPD的发生率部分与EBV特异性T淋巴细胞应答的数量和/或质量不足有关。我们的实验室项目专注于开发有效的策略，以“增强”细胞免疫监视机制，以治疗和预防潜在免疫缺陷患者的EBV-LPD。我们已经开发了一种可复制的小动物模型，可以密切模仿人类EBV-LPD，几种实验性治疗策略，以提供EBV编码的多肽靶蛋白，并与行业和非营利组织合作，合成疫苗，以预防EBV-LPD。在这里，我们提出利用我们在过去几年中开发的工具来系统地测试用选择性EBV裂解性和潜伏性全长多肽接种疫苗以预防EBV-LPD的功效。这个重大机遇奖将提供资金，以完成所有基础科学工作，以确定关键的EBV靶点，确认生物标志物以测量对疫苗的免疫反应，并进行临床前测试，以确定有前途的疫苗候选蛋白，然后在我们合作伙伴的帮助下，继续进行临床开发，为HIV+患者以及其他免疫抑制患者群体接种疫苗。该项目有很大的潜力对公共卫生、创造就业和经济增长产生影响。

DESCRIPTION (provided by applicant): Patients infected with HIV are at increased risk of developing malignant B cell lymphoproliferative diseases (LPD). The majority of these LPDs are positive for the Epstein-Barr virus (EBV), run an aggressive clinical course and are associated with a poor prognosis. EBV is an oncogenic, human herpes virus that infects more than 90% of adults worldwide and is associated with a wide spectrum of malignancies. The incidence of EBV- LPD in HIV-infected patients is, in part, related to the inadequate quantity and or quality of EBV-specific T lymphocyte response. We hypothesize that deficiency of cellular immunity against EBV lytic and latent antigens leads to increased risk of EBV-LPD, and vaccine-enhanced EBV-specific immunity will restore protection and prevent the development of EBV-LPD in this high risk population. We utilized a SCID mouse model which, when engrafted with human leukocytes from healthy EBV seropositive donors, spontaneously develops human EBV-LPD. We discovered several EBV latent and lytic antigens recognized by human CD8(+) T cells when the disease is controlled in vivo. Furthermore, we validated the recognition of these same antigens in iatrogenically immune suppressed patients with EBV-LPD while successfully controlling their disease in vivo following the reduction of their immune suppressive regimen. We cloned several EBV genes into an adeno-associated and adenoviral constructs, infected human antigen presenting cells and demonstrated robust autologous T cell expansion. Using HLA-specific tetramers loaded with immune dominant peptides derived from BZLF, we documented that In vivo expansion of BZLF1-specific T cells occurring in these patients correlated with EBV+ tumor regression and improved patient survival. With the support of Leukemia Lymphoma Society and corporate partners, we have recently completed a large scale purification of BZLF1 and are initiating preclinical toxicity studies for a planned pre IND meeting over the next year. Because a comprehensive EBV vaccine will likely require multiple EBV protein targets, we propose to complete a characterization of 4 additional target proteins and perform preclinical analysis to identify promising immunogens that may be further developed clinically. This Grand Opportunities grant will accomplish three specific aims: (1) characterize the human cellular response across various HLA types in response to each of the 5 proposed full length gene products in vitro in order to identify the optimal candidate gene product(s) to include in the vaccination strategy; (2) assess the efficacy of full length purified viral polypeptide preparations in stimulating and maintaining EBV specific memory T cell expansion and preventing fatal human EBV- associated lymphoproliferative disorder in our chimeric mouse-human model of EBV-LPD and (3) scale up production of full length candidate polypeptides for further characterization, evaluation of optimal delivery and adjuvant activity, toxicity evaluation, biomarker validation and immunogenicity studies. Once we have completion the above basic exploratory studies with the support of this grant, we will have identified the optimal viral target(s) that are "seen" across a broad HLA spectrum and be in a position to apply for an IND to conduct Phase I trials for safety of delivering specific vaccine preparations to HIV+ patients who are at high risk of developing EBV-LPD. Ultimately, a preventive approach for such viral-driven malignancies will likely prove to be more effective, less expensive, and hold great promise for benefitting more people worldwide by further reducing the incidence EBV-LPD and improving the quality of life of patients infected with HIV. PUBLIC HEALTH RELEVANCE: People infected with the Human Immune Deficiency virus (HIV) are at increased risk of developing malignant B cell lymphoproliferative diseases (LPD). Most of these LPDs are positive for Epstein-Barr virus (EBV-LPD), run an aggressive clinical course and are associated with a poor prognosis. Healthy, immune competent people do not develop EBV-LPD because of a highly efficient, adaptive cellular, antigen-specific immune response. The incidence of EBV-LPD in HIV-infected patients is, in part, related to the inadequate quantity and or quality of EBV-specific T lymphocyte response. Our laboratory program has focused on developing efficient strategies to "boost" cellular immune surveillance mechanisms to treat and prevent EBV-LPD in patients with underlying immune deficiency. We have developed a reproducible small animal model that closely mimics human EBV-LPD, several experimental therapeutic strategies to deliver EBV-encoded polypeptide target proteins, and partnerships with industry and not-for profit organizations to synthesize a vaccine to prevent EBV-LPD. Here we propose to utilize tools that we have developed over the past several years to systematically test the efficacy of vaccinating with selective EBV lytic and latent full length polypeptides to prevent EBV-LPD. This Grand Opportunities Award will provide funding to complete all basic scientific work to identify the key EBV targets, confirm biomarkers to measure immune response to the vaccine, and perform preclinical testing to identify promising vaccine candidate proteins that can then, with the help of our partners, move on towards clinical development to vaccinate HIV+ patients and, perhaps other immune suppressed patient groups. The project has great potential to make an impact on public health, job creation and economic growth.