Elucidation of Pathoptysiological Roles of Immune Chemokines

该项目的目的是阐明免疫趋化因子的病理生理作用，主要针对淋巴细胞和树突状细胞。今年的主要成就如下。(1)我们发现，促炎细胞因子如IL-1和TNFα有效诱导正常人表皮角质形成细胞表达LARC/CCL 20，该趋化因子已知选择性吸引未成熟树突状细胞和α4β7阳性记忆/效应T细胞vua CCR 6。我们还发现，特应性皮炎（AD）的病变皮肤往往含有表皮角质形成细胞产生LARC和CCR 6+细胞的表皮层下的广泛积累。此外，我们发现AD患者的血浆样本通常含有升高的LARC水平。总的来说，这些结果支持LARC在AD中的重要病理作用。(2)我们发现LARC的表达在粘膜上皮细胞中被促炎细胞因子如IL-1和TNFα强有力地诱导。毛皮 关于我们 此外，我们分析了这些细胞因子对LARC启动子的激活机制，发现距转录起始位点-96 ~-87bp的NF-κ B位点对LARC启动子的诱导是必需的。(3)我们发现，TARC/CCL 17和MDC/CCL 22在AD患者血浆中显著升高，这两种已知通过CCR 4吸引Th 2型记忆/效应T细胞和趋肤CLA+记忆/效应T细胞的细胞。此外，我们发现血小板含有TARC，并且其含量在AD患者的血小板中显著升高。我们进一步发现IFN-γ诱导正常人表皮角质形成细胞表达TARC和MDC。TARC和MDC在AD的发病机制中起重要作用。此外，IFN-γ也是Th 1趋化因子的有效诱导剂，其可能通过诱导一组同时吸引Th 1和Th 2细胞的趋化因子而在AD发病机制中起关键作用。(4)我们发现，在白色念珠菌感染的慢性炎症皮肤以及淋巴结中，大部分成熟树突状细胞产生MDC，并与表达CCR 4的T细胞聚集。因此，MDC可能在DC-T细胞相互作用中发挥重要作用。(5)我们发现，在小鼠哮喘模型诱导的引发与随后吸入卵清蛋白，治疗与抗mTARC单克隆抗体有效地阻断肺浸润的淋巴细胞和嗜酸性粒细胞和乙酰甲胆碱诱导的气道阻力的升高。因此，TARC可能在哮喘中发挥重要作用。(6)我们发现，在多发性硬化（MS）患者中，在加重期脑脊液中表达CCR 5或CXCR 3的淋巴细胞的频率增加，而缓解后表达CCR 5的淋巴细胞的频率降低。这些结果支持了MS发病机制中的Th 1偏向性免疫应答。（7）我们制备了针对小鼠趋化因子如MDC、LARC和SLC/CCL 21的单克隆抗体，但未能获得具有中和活性的抗体。(8)我们将TARC基因敲除小鼠和αE整合素基因敲除小鼠与BALB/c和C57 BL/6小鼠反复回交，并建立了同基因品系。少

The aim of the project has been to elucidate the pathophysiological roles of the immune chemokines, which are mainly directed to lymphocytes and dendritic cells. The main accomplishments of this year are as follows. (1) We showed that the proinflammatory cytokines such as IL-1 and TNFα potently induced normal human epidermal keratinocytes to express LARC/CCL20, the chemokine known to selectively attracts immature dendritic cells and α4β7-positive memory/effector T cells vua CCR6. We also showed that the lesional skin of atopic dermatitis (AD) often contained epidermal keratinocytes producing LARC and extensive accumulation of CCR6+ cells beneath the epidermal layer. Furthermore, we showed that plasma samples from AD patients often contained elevated levels of LARC. Collectively, these results support an important pathologenic role of LARC in AD. (2) We showed that expression of LARC was potently induced in mucosal epithelial cells by proinflammatory cytokines such as IL-1 and TNFα. Fur … More thermore, we analysed the activation mechanism of the LARC promoter by these cytokines and showed that an NF-kB site from -96 to -87bp from the transcriptional initiation site was essential for the induction of the LARC promoter. (3) We showed that TARC/CCL17 and MDC/CCL22, both known to attract Th2-type memory/effector T cells and skin-seeking CLA+ memory/effector T cells via CCR4, were significantly evevated in the plasma of AD patients. Furthermore, we found that platelets contained TARC and its contents were dramatically elevated in platelets from AD patients. We further showed that IFN-γinduced normal human epidermal keratinocytes to express TARC and MDC. Collectively, TARC and MDC may play important roles in the pathogenesis of AD. Furthermore, IFN-γ, which is also known to be apotent inducer of Th1-attracting chemokines, may be a critical factor in AD pathogenesis by inducing a set of chemokines attracting both Th1 and Th2 cells. (4) We showed that a large fraction of mature dendritic cells produced MDC and were clustered with CCR4-expressing T cesss in chronically inflamed skin infected with Candida albicans as well as in lymph node. Thus, MDC may play an important role in DC-T cell interactions. (5) We showed that in an asthmatic model in mice induced by priming with and subsequent inhalating of ovalbumin, the treatment with anti-mTARC monoclonal antibody efficiently blocked lung infiltrating of lymphocytes and eosinophils and elevation of methacholine-induced airway resistance. Thus, TARC is likely to play an important role in asthma. (6) We showed that in patients with multiple sclerosis (MS), the frequencies of lymphocytes expressing CCR5 or CXCR3 was increased in the cerebrospinal fluid during exacerbation, while the frequencies of CCR5-expressinglymphocytes were decreased after remission. These results support the Th1-biased immune responses in the pathogenesis of MS. (7) We generated monoclonal antibodies to mouse chemokines such as MDC, LARC and SLC/CCL21 in Armenisan hamsters but could not get antibodies with neutralizing activities. (8) We have repeatedly backcrossed TARC-knockout mice and αE integrin-knockout mice into BALB/c and C57BL/6 mice and developed the syngeneic strains. Less