Development of novel, safe and efficacious Coxiella burnetii vaccine

 描述（由申请人提供）：虽然Q热首次被诊断近80年前，一种有效的疫苗，提供长期保护，从C。贝氏体感染和重复加强给药的安全性仍然不可用。我们已经确定单独的CD 4或CD 8 T细胞（没有B细胞）足以保护免受毒性I C期。贝氏体，并且CD 8 T细胞应答与较少有害的组织损伤相关。其他研究表明I C期抗体。贝氏菌LPS也可能是有效的，并且应该在任何新的疫苗制剂中考虑。I期C。已知贝氏菌LPS以不同方式影响其受体TLR 4和下游对C.在小鼠和人中的贝氏体，减少小鼠作为人类Q热模型的效用。为了克服小鼠中的这种缺陷，我们将利用hTLR 4/MD 2转基因小鼠模型（表达人TLR 4/MD 2），我们最近显示其比野生型小鼠对低剂量C更敏感。贝氏体感染这种新的小鼠将使我们能够更好地分析对I C期的体内反应。贝氏菌LPS及其作为疫苗抗原的用途。为了开发一种新的Q热疫苗，我们计划使用一种新型的递送平台，该平台使用P22病毒样颗粒（P22 VLP），即使在没有特异性抗原的情况下，也能诱导免疫样反应，非特异性地保护小鼠免受不同病毒和细菌病原体的侵害，并最大限度地减少与这些病原体相关的组织发病率。P22 VLP可以被独特地工程化以在内表面和外表面上表达抗原，我们已经表明这分别导致保护性CD 8 T细胞和B细胞应答的选择性增强。具体地说，我们的初步结果表明，P22 VLP可以被工程化以有效地诱导抗原特异性非损伤性免疫应答，其可以适应可许可的C.贝氏体疫苗因此，我们假设VLP可以被工程化以产生有效的C。贝氏体疫苗仅在肺局部诱导保护性和非损伤性适应性免疫应答（如CD 8 T细胞和抗体应答）。由于VLP引起的免疫应答的非损伤性，我们进一步假设该疫苗对于可重复施用是安全的。为了验证这一假设，我们将追求以下具体目标。目的1）产生诱导CD 8 T细胞介导的保护的VLP构建体。这将通过鉴定C来完成。贝氏体免疫显性CD 8 T细胞表位，其将在P22 VLP的内表面上表达。目的2）产生诱导抗LPS抗体介导的保护的VLP构建体。VLP递送的I期C的功效。将在用VLP构建体免疫的人源化TLR 4/MD 2小鼠中测定贝氏体LPS，所述VLP构建体在P22 VLP内侧表达免疫显性CD 8 T细胞表位，在相同VLP外侧表达LPS。

 DESCRIPTION (provided by applicant): Although Q fever was first diagnosed nearly 80 years ago; an efficacious vaccine that provides long- term protection from C. burnetii infection and is safe for repeated booster administrations is still unavailable. We have determined that either CD4 or CD8 T cells alone (without B cells) are sufficient for protection from virulent phase I C. burnetii and that the CD8 T cell response is associated with less deleterious tissue damage. Others have shown that antibodies to phase I C. burnetii LPS may be efficacious as well, and should be considered in any new vaccine formulation. Phase I C. burnetii LPS is known to differently affect its receptor, TLR4, and the downstream immune responses to C. burnetii in mice and humans, diminishing the utility of mice as a model of Q fever in humans. To overcome this deficiency in mice, we will utilize an hTLR4/MD2 transgenic mouse model (expressing human TLR4/MD2), which we have recently shown is more susceptible than wildtype mice to low dose C. burnetii infection. This new mouse will allow us to better analyze the in vivo response to phase I C. burnetii LPS and its utility as a vaccine antigen. To develop a new vaccine for Q fever, we plan on using a novel delivery platform that uses P22 virus-like particles (P22 VLPs), which even in the absence of specific antigen induce adjuvant-like responses that nonspecifically protect mice from different viral and bacterial pathogens and minimize tissue morbidity associated with these pathogens. The P22 VLP can be uniquely engineered to express antigens on both the internal and external surfaces, which we have shown leads to selective enhancement of protective CD8 T cell and B cell responses, respectively. Specifically, our preliminary results suggest that P22 VLPs can be engineered to effectively induce antigen-specific non-damaging immune responses that could accommodate the requirements for a licensable C. burnetii vaccine. Thus, we hypothesize that VLPs can be engineered to generate an effective C. burnetii vaccine that induces only the protective and non-damaging adaptive immune responses (such as both CD8 T cell and antibody responses) locally in the lungs. Due to the non-damaging nature of the immune response elicited by the VLPs, we further hypothesize that this vaccine will be safe for repeatable administration. To test this hypothesis, we will pursue the following Specific Aims. Aim 1) Generate a VLP construct that induces CD8 T cell-mediated protection. This will be done by identification of C. burnetii immunodominant CD8 T cell epitopes that will be expressed on the internal surface of the P22 VLPs. Aim 2) Generate a VLP construct that induces anti-LPS antibody-mediated protection. The efficacy of VLP-delivered phase I C. burnetii LPS will be determined in humanized TLR4/MD2 mice immunized with VLP constructs expressing immunodominant CD8 T cell epitopes on the inside of the P22 VLPs and LPS on the outside of the same VLPs.