The role of Chlamydia trachomatis specific HLA-E restricted CD8 T cell responses in clearance of infection

项目摘要 沙眼衣原体（CT）感染仍然是最常见的细菌性传播感染（STI） 在全球范围内，每年报告的新CT感染超过1.2亿例。在美国，非裔美国人和女性 都受到CT感染的影响。尽管最近报告了超过150万例CT病例， 美国，这可能是一个低估，因为上述弱势群体的经验不平等， 获得常规医疗服务。妇女经历CT感染的负担更大，由于许多生殖 与这种感染有关的并发症。迄今为止，防控力度没有明显减弱 CT感染率。此外，高达20%的感染者在一年内再次感染，这表明 短暂或次优的免疫力。在小鼠模型和人类研究的背景下，我们和其他人已经 先前的研究表明，产生IFN-γ的CD 4 + T细胞在衣原体清除和保护免受 再感染然而，最近对人类的研究表明，CD 8 T细胞可能在CT感染中发挥作用， 好. CD 8 T细胞在感染细胞通过经典MHC-1呈递的肽的背景下识别病原体。 Ia等位基因（在人类中，HLA-A、B或C）或非经典MHC-Ib等位基因（在人类的情况下，HLA-E）。先前工作 HLA-E限制性CD 8 T细胞（HLA-E/CD 8 s）在控制免疫应答中发挥重要的免疫调节作用。 几种细胞内细菌病原体，如分枝杆菌和沙门氏菌。HLA-E/CD 8 s在乳腺癌中的作用 CT感染，因为它涉及CT感染的清除是未知的。之前的两项人类研究检查了CD 8 对CT的T细胞应答间接证明了受非经典HLA-I等位基因限制的应答。然而，在这方面， 这种限制的确切性质以及此类细胞在疾病发病机制中与清除有关的作用 CT感染的定义不明。由于HLA-Ia和HLA-Ib（即，HLA-E）普遍共表达， 需要适当的分子工具和方法来剖析CD 8 T细胞的独特贡献 对通过这些等位基因中的每一个呈递的肽做出响应。我们最近生成了HLA-E*01：01， E*01：03特异性细胞资源，使我们能够识别HLA-E/CD 8，并评估其在免疫系统中的相关性。 CT感染的背景。具体地说，我们的初步数据表明，HLA-E/CD 8产生CD 107 a/IFN-γ/TNF-α。 α在CT感染清除的女性中优先检测到。我们的总体假设是HLA-E限制性 CD 8 T细胞将在女性CT感染的清除中发挥重要作用。在目标1中，我们将确定 CT特异性HLA-E限制性CD 8 T细胞是否在女性CT感染的清除中发挥作用。在目标2中， 将确定CT特异性HLA-E限制性CD 8 T细胞是否可以从CT初治女性供体中引发， 当前或既往CT感染。总之，我们完成的研究将证明生物学相关性， HLA-E限制性CD 8 T细胞应答在清除CT感染中的功能性，因此具有直接应用 用于预防性CT疫苗的免疫原选择。

PROJECT SUMMARY Chlamydia trachomatis (CT) infection remains the most prevalent bacterial sexually transmitted infection (STI) worldwide, with over 120 million new CT infections reported annually. In the US, African Americans and women are disproportionally affected by CT infection. Although over 1.5 million CT cases were recently reported in the US, this is likely an underestimation as the above-mentioned vulnerable population experiences inequities in access to routine healthcare. Women experience a greater burden of CT infection due to many reproductive complications associated with this infection. To date, prevention and control efforts have not significantly reduced CT infection rates. In addition, up to 20% of infected persons are reinfected within a year suggesting either a short lived or suboptimal immunity. In the context of both murine models and human studies, we and others have previously showed a role of IFN-γ-producing CD4+ T cells in chlamydia clearance and protection against reinfection. Recent studies in humans have however shown that CD8 T cells could play a role in CT infection as well. CD8 T cells recognize pathogens in the context of peptides presented by an infected cell via classical MHC- Ia alleles (in humans, HLA-A, B or C) or non-classical MHC-Ib alleles (in case of humans, HLA-E). Prior work has shown that HLA-E restricted CD8 T cells (HLA-E/CD8s) exert an important immune-regulatory role in control of several intracellular bacterial pathogens such as Mycobacterium and Salmonella. The role of HLA-E/CD8s in CT infection as it pertains to clearance of CT infection is unknown. Two previous human studies examining CD8 T cell responses to CT indirectly demonstrated responses restricted by non-classical HLA-I alleles. However, the precise nature of this restriction and the role of such cells in disease pathogenesis as it pertains to clearance of CT infection was not defined. Since HLA-Ia and HLA-Ib (i.e., HLA-E) are ubiquitously co-expressed, appropriate molecular tools and methodologies are needed to dissect the unique contributions of CD8 T cells responding to peptides presented via each of these alleles. We have recently generated HLA-E*01:01 and E*01:03 specific cellular resources that allowed us to identify HLA-E/CD8s and to assess their relevance in the context of CT infection. Specifically, our preliminary data shows that HLA-E/CD8s producing CD107a/IFN-γ/TNF- α are preferentially detected in women who clear CT infection. Our overall hypothesis is that HLA-E restricted CD8 T cells will play an important role in clearance of CT infection in women. In Aim 1, we will determine if CT-specific HLA-E restricted CD8 T cells play a role in the clearance of CT infection in women. In Aim 2, we will determine if CT-specific HLA-E restricted CD8 T cells can be primed from CT naïve female donors with no current or prior CT infection. In summary our completed studies will demonstrate the biological relevance and functionality of HLA-E restricted CD8 T cell response in clearance of CT infection and thus has direct applications for immunogen selection for a preventative CT based vaccine.