Naturally Occurring IgM Anti-Leucocyte Autoantibodies Protect Against Renal IRI

描述（由申请方提供）：本多PI提案的总体目标是研究天然存在的IgM抗白细胞自身抗体在抑制缺血再灌注损伤（IRI）后发生的炎症过程中的作用。我们和其他人观察到，一个子集（30%）的患者与高水平的IgM-ALA有轻微或无排斥反应后，肾或心脏移植。我们发现，IgM-ALA以高度特异性的方式与白细胞受体结合，尽管存在补体，但在体温下不会导致白细胞死亡。此外，我们发现IgM-ALA（i）结合CD 4和CD 3受体（但不结合HLA、IL-2 R）并抑制T细胞活化、增殖和某些促炎细胞因子（TNF-1、IL-2）的产生，但不抑制其他促炎细胞因子（IL-6和IL-8）的产生，（ii）结合趋化因子受体并抑制趋化性。基于这些发现，我们质疑IgM-ALA是否下调伴随肾脏IRI的炎症.缺血性损伤后释放的糖脂在细胞因子存在下由驻留树突状细胞（DC）加工并呈递给NKT细胞，NKT细胞被激活并产生细胞因子（特别是IFN？）通过吸引和激活体循环中的白细胞来扩大炎症过程。我们认为，IgM-ALA可通过与参与细胞活化的受体结合并抑制白细胞趋化性来下调炎症过程。为了验证我们的假设，我们使用IgM缺陷小鼠（IgMko小鼠），并显示这些小鼠相对于其WT-B6对应物发生严重的肾IRI。我们提出了3个目标：目标1将测试假设IgM-ALA是保护肾IRI。为了检验这一假设，我们计划在IgMko小鼠中进行肾IRI，并用纯化的B1细胞（WT小鼠中IgM-ALA的来源）和从WT小鼠获得的纯化血浆IgM对其进行拯救。我们还将通过向WT小鼠施用IgM来测试IgM的治疗价值。目的2将检验以下假设：IgM缺陷小鼠中引起更严重肾IRI的增强的炎症过程是由于缺乏IgM介导的树突状细胞（DC）/自然杀伤T（NKT）细胞途径以及下游IL 17途径中的细胞抑制，而不是由于IgM缺陷小鼠中未掩蔽的某些其他机制。我们将用阻断抗体阻断IgMko小鼠中的这一通路，并用白喉毒素消耗DC。目的3验证IgM-ALA通过与细胞受体结合，减弱DC和NKT细胞的功能以及白细胞的趋化性和功能，从而抑制炎症过程的假说。所提出的研究的意义在于，在人类中的观察结果支持了天然存在的IgM-ALA可能消除与急性肾损伤（阿基）相关的炎症的假设。我们的初步数据提供了强有力的证据，证明这些天然存在的IgM-ALA确实在阿基中具有保护作用，因此这些研究将确定天然存在的IgM-ALA的组织保护机制。 公共卫生相关性： 急性肾损伤仍然是一个公共卫生问题。发病率继续上升，发病率和死亡率高得令人无法接受。这些研究代表了一种治疗阿基的新治疗方法，以及一种可以在阿基和其他先天免疫疾病的人体临床试验中快速推进的方法。

DESCRIPTION (provided by applicant): The overall goal of this multi-PI proposal is to investigate the role of naturally occurring IgM anti-leucocyte autoantibodies in inhibiting inflammatory processes that occur after ischemia-reperfusion injury (IRI). We and others observed that a subset (30%) of patients with high levels of IgM-ALA had minimal or no rejections after a kidney or heart transplant. We showed that IgM-ALA bind to leucocyte receptors in a highly specific manner and at body temperature does not cause leucocyte cell death despite presence of complement. Furthermore, we showed that IgM-ALA (i) bind to CD4 and CD3 receptors (but not HLA, IL-2R) and inhibit T cell activation, proliferation and production of certain proinflammatory cytokines (TNF-1, IL-2) but not others (IL-6 and IL-8), (ii) bind to chemokine receptors and inhibit chemotaxis. Based on these findings we questioned whether IgM- ALA downregulate inflammation that accompanies renal IRI. Glycolipids released after ischemic injury are processed and presented by resident dendritic cells (DC), in presence of cytokines, to NKT cells, which get activated and produce cytokines (in particular IFN?) to amplify the inflammatory process by attracting and activating leucocytes from the systemic circulation. We posit that IgM-ALA could downregulate the inflammatory process by binding to receptors involved in cell activation and inhibiting leucocyte chemotaxis. To test our hypothesis, we used mice deficient in IgM (IgMko mice) and showed that these mice develop severe renal IRI relative to their WT-B6 counterparts. We propose 3 aims: Aim 1 will test the hypothesis IgM-ALA is protective in renal IRI. To test this hypothesis we plan to perform renal IRI in IgMko mice and rescue them with purified B1 cells (source of IgM-ALA in WT mice) and also with purified plasma IgM, obtained from WT mice. We will also test the therapeutic value of IgM by administering IgM to WT mice. Aim 2 will test the hypothesis that the enhanced inflammatory process causing more severe renal IRI in mice deficient in IgM results from lack of IgM mediated inhibition of cells in the dendritic cell (DC)/natural killer T (NKT) cell pathway as well as the downstream IL17 pathway and not from some other mechanism that is unmasked in mice deficient in IgM. We will interrupt this pathway in IgMko mice with blocking antibodies and depleting DCs with diptheria toxin. Aim 3 will test the hypothesis that IgM-ALA inhibits the inflammatory process by binding to cell receptors and attenuating the function of DC and NKT cells and chemotaxis and function of leucocytes. The significance of the studies proposed is that it was observations in humans that undergird the hypothesis that naturally occurring IgM-ALA might abrogate inflammation associated with acute kidney injury (AKI). Our preliminary data provide strong evidence that indeed these naturally occurring IgM-ALA are protective in AKI and thus these studies will define mechanisms of tissue protection by naturally occurring IgM-ALA. PUBLIC HEALTH RELEVANCE: Acute kidney injury continues to remain a public health concern. The incidence continues to rise and the morbidity and mortality is unacceptably high. These studies represent a novel therapeutic approach for the treatment of AKI and an approach that could be targeted for rapid advancement in human clinical trials in AKI and other disorders of innate immunity.