IL-2 Family Cytokines and their Receptors--Biology of the IL-7/TSLP Systems

IL-2受体和相关的细胞因子受体系统正在研究中，以澄清正常，肿瘤和免疫缺陷状态下的T细胞免疫应答。在T细胞被抗原激活后，T细胞免疫应答的幅度和持续时间由产生的IL-2的量、表达的受体水平和每个事件的时间过程决定。IL-2受体含有三条链，IL-2 Ra、IL-2 Rb和gc。伦纳德博士于1984年克隆了IL-2 Ra，我们于1986年发现了IL-2 Rb，并于1993年报道了人类中GC链突变导致X连锁严重联合免疫缺陷（XSCID，具有T-B+NK-表型）。我们在1995年报道了GC相关激酶Jak 3的突变导致与XSCID难以区分的常染色体隐性形式的SCID，并且在1998年报道了T-B+NK+ SCID由IL 7 R基因突变引起。基于我们实验室和其他实验室的工作，先前显示gc被IL-2、IL-4、IL-7、IL-9、IL-15和IL-21的受体共享。 在麻省理工学院的Harvey Lodish实验室的合作下，我们先前报道了胸腺基质淋巴细胞生成素（TSLP）受体的克隆。然后，我们证明了TSLP，与文献的意义相反，在人类和小鼠中通过CD 4 + T细胞发挥主要作用，并且先前与Scott Durum一起表明TSLP和IL-7，它们共享IL-7 Ra作为受体组分，都驱动调节性T细胞的发育，并且TSLP还通过CD 8 + T细胞上的受体发出信号。TSLPR与gc最相关，并且我们表明，尽管TSLP和IL-7共享IL-7受体α链，但TSLP和IL-7的功能是不同的。我们发现TSLP促进CD 4 T细胞发育，而IL-7和IL-15也共享gc，有利于CD 8 T细胞发育，TSLP在哮喘变应性肺部炎症小鼠模型的发展中起关键作用，并且CD 4 + T细胞对其在该模型中的作用至关重要。在过去的一年中，我们证明并报道了TSLP信号通过JAK 1和JAK 2而不是通过Tek家族激酶，如文献中所建议的介导人和小鼠原代T细胞中STAT 5的活化，并且STAT 5介导TSLP诱导的CD 4 + T细胞的存活和增殖。我们发现JAK 1与IL 7 R相关，JAK 2与TSLPR相关，从而阐明了TSLP信号传导的基础，并提供了使用JAK 1和JAK 2的组合来介导STAT 5活化的细胞因子的第一个例子。我们以前也证明，树突状细胞，这是已知的响应TSLP，意外地产生TSLP，包括后的挑战与屋尘螨提取物，这表明一个可能的自分泌机制，他们对这种细胞因子的反应。与Arya Biragyn一起，我们还证明了人类和小鼠实体瘤产生的TSLP有助于乳腺癌和黑色素瘤模型系统的进展和转移，并且TSLP的抗癌作用是通过其对T细胞的作用介导的，并产生IL-10和IL-13。 在过去的一年里，随着N。Hirasawa在日本的研究中，我们报道了TSLP反应性是帕利佛明介导的移植物抗宿主病保护所必需的，而且，TSLP是由二甲苯诱导的，与苦氯诱导的过敏性炎症加重相关。在另一项研究中，用B. Anne Croy在多伦多发表的研究中，我们报道了与小鼠子宫NK细胞表达IL-7 Ra的时间相关的发现。我们发现在小鼠蜕膜中发现表达IL-7 Ra的细胞，并且发现其在gd 10.5蜕膜中的子宫NK亚群中表达，并且子宫NK细胞也表达TSLPR。在正常妊娠期间，子宫NK细胞的发育不需要IL-7或TSLP，但每种细胞因子对植入不同区域的子宫NK细胞具有功能性影响。我们还继续研究了与过敏性炎症相关的TSLP。 总体而言，这些研究增加了我们对gc家族细胞因子和TSLP信号传导的理解，阐明了与免疫缺陷、过敏、自身免疫和癌症以及淋巴稳态相关的分子机制。

The IL-2 receptor and related cytokine receptor systems are being studied to clarify the T cell immune response in normal, neoplastic, and immunodeficient states. Following T-cell activation by antigen, the magnitude and duration of the T-cell immune response is determined by the amount of IL-2 produced, levels of receptors expressed, and time course of each event. The IL-2 receptor contains three chains, IL-2Ra, IL-2Rb, and gc. Dr. Leonard cloned IL-2Ra in 1984, we discovered IL-2Rb in 1986, and reported in 1993 that mutation of the gc chain results in X-linked severe combined immunodeficiency (XSCID, which has a T-B+NK- phenotype) in humans. We reported in 1995 that mutations of the gc-associated kinase, Jak3, result in an autosomal recessive form of SCID indistinguishable from XSCID and in 1998 that T-B+NK+ SCID results from mutations in the IL7R gene. Based on work in our lab and others, gc was previously shown to be shared by the receptors for IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21. In collaboration with Harvey Lodish's lab at MIT, we previously reported the cloning of the receptor for thymic stromal lymphopoietin (TSLP). We then demonstrated that TSLP, counter to the sense of the literature, exerted major actions via CD4+ T cells in both humans and mice, and previously showed with Scott Durum that TSLP and IL-7, which share IL-7Ra as a receptor component, both drive the development of regulatory T cells, and that TSLP also signals via receptors on CD8+ T cells. TSLPR, is most related to gc, and we showed that although both TSLP and IL-7 share the IL-7 receptor alpha chain, the function of TSLP and IL-7 are distinctive. We showed that TSLP promotes CD4 T cell development whereas IL-7 and IL-15, which also share gc, favor CD8 T cell development, and that TSLP plays a critical role in the development of allergic lung inflammation mouse model of asthma, and that CD4+ T cells are essential for its action in that model. In the previous year, we demonstrated and reported that TSLP signals via JAK1 and JAK2 rather than through a Tek family kinase, as had been suggested in the literature to mediate the activation of STAT5 in both human and mouse primary T cells, and that STAT5 mediated TSLP-induced survival and proliferation of CD4+ T cells. We showed that JAK1 associates with IL7R and JAK2 with TSLPR, thus clarifying the basis for TSLP signaling and provided the first example of a cytokine using the combination of JAK1 and JAK2 to mediate the activation of STAT5. We also previously demonstrated that dendritic cells, which were known to respond to TSLP, unexpectedly produce TSLP, including after challenge with house dust mite extract, suggesting a possibly autocrine mechanism for their responsiveness to this cytokine. With Arya Biragyn, we also demonstrated that TSLP produced by human and mouse solid tumors contributes to progression and metastasis in breast cancer and melanoma model systems and that the cancer-romoting action of TSLP is mediated via its action on T cells, with the production of IL-10 and IL-13. In the past year, with N. Hirasawa in Japan, we reported that TSLP responsiveness was required for palifermin-mediated protection from graft versus host disease and that moreover, TSLP was induced by xylene and associated with exacerbation of picryl chloride-induced allergic inflammation. In another study, with B. Anne Croy in Toronto, we reported findings related to the timing of expression of IL-7Ra expression by mouse uterine NK cells. We found that cells expressing IL-7Ra were found in mouse decidua and found that it was expressed in a uterine NK subset in gd 10.5 decidua, and uterine NK cells also expressed TSLPR. Neither IL-7 nor TSLP was required for the development of uterine NK cells during normal pregnancy, but each cytokine had functional impact on uterine NK cells in separate regions of implantation. We also have continued our studies of TSLP related to allergic inflammation. Overall, these studies have increased our understanding of signaling by gc family cytokines and TSLP, clarifying molecular mechanisms that are relevant to immunodeficiency, allergy, autoimmunity, and cancer, as well as to lymphoid homeostasis.