THE ROLE OF UROKINASE IN LUNG T LYMPHOCYTE RESPONSES

我们已经证明，uPA是有效的肺防御新生隐球菌（C。neo）体内感染。 宿主对C. neo完全依赖于T细胞。 在不存在uPA的情况下，CD 4细胞的肺蓄积不能响应感染而发生，并且uPA阴性/阴性动物死于播散性隐球菌病。 我们发现，在缺乏uPA的情况下，T细胞损伤不是C.尼欧 在体内，uPA阴性/阴性小鼠不能响应于卡氏肺孢子虫而增加肺CD 4细胞，并且不能清除感染。 我们已经发现，T细胞增殖反应在uPA的情况下严重受损。 在体外，uPA阴性/阴性淋巴细胞不经历抗原特异性增殖，它们也不响应于由CD 3交联或由有丝分裂原产生的TCR介导的信号而增殖。体内对T细胞特异性病原体的有效宿主防御;以及由抗原、有丝分裂原或通过CD 3交联诱导的体外T细胞增殖测定中的正常应答，通过主要通过TCR-蛋白激酶级联介导的共同信号传导途径连接，并与由CD 28和CD 25递送的共刺激信号偶联。 我们的假设是，在不存在uPA的情况下，通过Jak/STAT的T淋巴细胞细胞内信号传导减少，导致细胞因子产生不足和细胞因子反应性降低。 Jak/STAT信号传导的缺乏导致T细胞活化和增殖受阻;并且T细胞对进一步的TCR介导的信号传导无反应。1.定位T细胞信号级联中的生化阻断。 a）确定uPA的不存在是否减少TCR介导的信号传导。 B）确定uPA的缺失是否减少了CD 28和CD 25介导的信号传导。 c）确定uPA是否激活鼠T淋巴细胞中的Jak/STAT信号传导。2.确定异常T细胞信号传导的功能后果。 a）确定淋巴细胞活化中对uPA的需求，如通过活化抗原的表达、细胞因子的产生和对IL-12的响应性所测量的。 B）确定uPA负/负淋巴细胞信号传导的缺陷是否导致无反应性、细胞周期停滞或凋亡。 3.测定uPA和uPAR在体外T细胞活化和增殖过程中的细胞表达和运输。 确定重组uPA是否可以逆转uPA负/负淋巴细胞中的功能异常。

We have demonstrated that uPA is required for effective pulmonary defense against Cryptococcus neoformans (C. neo) infection in vivo. Host defense against C. neo is absolutely T cell dependent. In the absence of uPA, lung accumulation of CD4 cells fails to occur in response to infection, and the uPA minus/minus animals die from disseminated Cryptococcosis. We found that the T cell impairment in the absence of uPA is not specific to C. neo. In vivo, uPA minus/minus mice fail to increase pulmonary CD4 cells in response to P. carinii, and do not clear the infection. We have found that T cell proliferative responses are profoundly impaired in the absence of uPA. In vitro, uPA minus/minus lymphocytes do not undergo antigen-specific proliferation, nor do they proliferate in response to TCR- mediated signals generated by CD3-cross-linking, or by mitogen. Effective host defense to T-cell specific pathogens in vivo; and normal responses in vitro T cell proliferation assays induced by antigen, mitogen, or by CD3-cross-linking, are linked by a common signaling pathway mediated primarily through the TCR-protein kinase cascade, and coupled to co-stimulatory signals delivered by CD28 and CD25. It is our hypothesis that in the absence of uPA, T lymphocyte intracellular signaling via Jak/STAT is diminished leading to inadequate cytokine production and diminished cytokine responsiveness. The lack of Jak/STAT signaling results in blocked T cell activation and proliferation; and T cell unresponsiveness to further TCR-mediated signaling. 1. Localize the biochemical block(s) in T cell signaling cascades. a) Determine if the absence of uPA diminishes TCR- mediated signaling. b) Determine if the absence of uPA diminishes CD28- and CD25-mediated signaling. c) Determine whether uPA activates Jak/STAT signaling in murine T lymphocytes. 2. Determine the functional consequences of aberrant T cell signaling. a) Determine the requirement for uPA in lymphocyte activation as measured by expression of activation antigens, elaboration of cytokines, and responsiveness to IL-12. b) Determine whether the defects in uPA minus/minus lymphocyte signaling result in anergy, cell cycle arrest, or apoptosis. 3. Determine the cellular expression and trafficking of uPA and uPAR during T cell activation and proliferation in vitro. Determine if recombinant uPA can reverse the functional abnormalities in uPA minus/minus lymphocytes.