Resistance of Beta 2 Microglobulin Null Mice to Sepsis

描述（由申请人提供）： β 2微球蛋白敲除小鼠缺乏CD 8 + T细胞和自然杀伤T细胞。与野生型小鼠相比，β 2微球蛋白敲除小鼠在盲肠结扎穿孔（CLP）引起的脓毒症期间表现出改善的存活率。通过注射抗去唾液酸GM 1进一步消耗自然杀伤细胞，可使CLP诱导的死亡率几乎完全耐受。这些观察结果背后的机制尚不清楚。然而，两种潜在的机制具有很高的可能性。首先，CD 8 + T、自然杀伤T和自然杀伤细胞可以通过放大促炎细胞因子和趋化因子的产生来影响先天免疫应答。这些细胞群也可以在炎症期间引起直接的细胞损伤。因此，假设CD 8 + T、自然杀伤T和自然杀伤细胞通过放大促炎反应和/或引起直接细胞损伤来促进或直接介导脓毒症诱导的死亡率。其次，β 2微球蛋白包含I类主要组织相容性复合物的β链和非经典抗原呈递分子CD 1。这两种分子分别对自身和外源抗原的呈递很重要，但它们在脓毒症期间调节炎症反应的作用尚不清楚。进一步假设I类主要组织相容性复合物、CD 1和/或未识别的β 2微球蛋白相关分子在脓毒症期间调节免疫应答中发挥作用。本研究项目旨在验证这些假设。目的1：确定CD 8 + T、自然杀伤T细胞和自然杀伤细胞、I类主要组织相容性复合物和CD 1在致死性腹腔内脓毒症发病机制中的特异性贡献。在对照小鼠和缺乏这些细胞群和抗原呈递分子的小鼠中，CLP后将测量死亡率、细菌计数、器官损伤、心血管功能和酸碱平衡。具体目标二：目的探讨腹腔内脓毒症时CD 8 + T细胞、自然杀伤T细胞和自然杀伤细胞、I类主要组织相容性复合物和CD 1在调节促炎反应中的作用。在对照小鼠和缺乏CD 8 + T、自然杀伤T和自然杀伤细胞、I类主要组织相容性复合体和CD 1的小鼠中，在CLP后测量腹腔内和全身细胞因子和趋化因子的产生。具体目标3：确定细胞溶解机制在致死性腹腔内脓毒症发病机制中的作用。我们将评估对照小鼠和CLP后CD 8 + T、自然杀伤T和自然杀伤细胞缺陷小鼠中穿孔素、颗粒酶、Fas和FasL的表达。将通过评估穿孔素缺陷和FasL缺陷小鼠的存活率、心血管功能、器官损伤和酸碱平衡来确定穿孔素/颗粒酶和Fas-FasL途径的功能作用。这些研究旨在确定脓毒性休克发病机制中重要的新机制，最终目标是为这种致命疾病过程开发新的治疗方法。

DESCRIPTION (provided by applicant): Beta2 microglobulin knockout mice are deficient in CD8+ T cells and natural killer T cells. Compared to wild type mice, beta2 microglobulin knockout mice exhibit improved survival during sepsis caused by cecal ligation and puncture (CLP). Further depletion of natural killer cells by injection of anti-asialoGM1 confers near complete resistance to CLP-induced mortality. The mechanisms underlying these observations are unknown. However, two potential mechanisms have high probability. Firstly, CD8+ T, natural killer T and natural killer cells can impact innate immune responses by amplifying production of pro-inflammatory cytokines and chemokines. These cell populations can also cause direct cellular injury during inflammation. Therefore, it is hypothesized that CD8+ T, natural killer T and natural killer cells facilitate or directly mediate sepsis-induced mortality by amplifying the pro-inflammatory response and/or causing direct cellular injury. Secondly, beta2 microgiobulin comprises the beta chain of the class I major histocompatibility complex and the non-classical antigen-presenting molecule CD1. Both of these molecules are important for presentation of self and foreign antigens, respectively, but their roles in regulating inflammatory responses during sepsis are unknown. It is further hypothesized that the class I major histocompatibility complex, CD1 and/or unrecognized beta2 microglobulin-associated molecules play a role in modulating the immune response during sepsis. This research project is designed to test these hypotheses. The following specific aims are proposed: Aim 1: To determine the specific contributions of CD8+ T, natural killer T and natural killer cells, the class I major histocompatibility complex and CD1 to the pathogenesis of lethal intra-abdominal sepsis. Mortality, bacterial counts, organ injury, cardiovascular function and acid-base balance will be measured following CLP in control mice and mice that are deficient in these cell populations and antigen-presenting molecules. Specific Aim 2: To determine the functional roles of CD8+ T, natural killer T and natural killer cells, the class I major histocompatibility complex and CD1 in regulating the pro-inflammatory response during lethal intra-abdominal sepsis. Intra-abdominal and systemic cytokine and chemokine production will be measured following CLP in control mice and mice that are deficient in CD8+ T, natural killer T and natural killer cells, the class I major histocompatibility complex and CD1. Specific Aim 3: To determine the role of cytolytic mechanisms in the pathogenesis of lethal intra-abdominal sepsis. We will evaluate expression of perforin, granzymes, Fas and FasL in control mice and mice that are deficient in CD8+ T, natural killer T and natural killer cells after CLP. The functional roles of the perforin/granzyme and Fas-FasL pathways will be determined by assessing survival, cardiovascular function, organ injury and acid-base balance in perforin-deficient and FasL-deficient mice. These studies are designed to define new mechanisms that are important in the pathogenesis of septic shock with the ultimate goal of developing new treatments for this lethal disease process.