Role of inflammation, innate resistance, and immunity in carcinogenesis.

在该项目的若干目标方面取得了进展，特别是在 TLR信号在调节成纤维细胞和树突状细胞的增殖和存活中的作用， 对人DC产生细胞因子的调节，对浆细胞样DC在 调节口服耐受性对NK细胞对弓形虫Th 1分化的影响 弓形虫感染、TNF、MyD 88和IL-18在结肠炎依赖性致癌作用中的作用肝 浆细胞样树突细胞有助于口服诱导的CD 8 + T细胞耐受（Immunity. 2008; 9：464-75）。肝脏被认为有助于全身T细胞对口服给药的耐受性。 吸收的抗原，尽管其致耐受作用的确切机制尚不清楚。这里 我们发现肝脏是口服抗原呈递的场所， (DC)可以耐受小鼠随后的CD 8 + T细胞引发，在半抗原特异性的模型中， 接触敏感性（CHS）。肝DC的致耐受性潜力仅限于浆细胞样 DC（pDC）通过暴露于半抗原而增强，并且需要CD 4 + T细胞。最后，在体内 pDC的消耗消除了口服耐受性并恢复了半抗原特异性CD 8 + T细胞和CHS 应答因此，pDC是致耐受性的，并且在口服耐受性中起重要作用。这些 目前正在扩展研究以分析肝脏pDC在其他耐受模型中的作用 特别是在测试是否需要pDC来诱导TNBS耐受性的模型中 结肠炎和癌变。我们已经产生了表达人类白喉毒素的小鼠， 受体和pDC上特异性的绿色荧光蛋白。这些老鼠可以用来 鉴定和体内消耗pDC，并且它们将用于旨在 体内鉴定和耗尽pDC。除了口服耐受模型外， 确定了肠固有层中TLR 9激活的pDC阻止了 在FoxP 3 + Treg中的幼稚CD 4 T细胞，我们正在将我们的研究扩展到其他模型， pDC参与免疫调节。弓形虫感染TAP 1缺陷小鼠 NK细胞IFN-γ产生受损，导致CD 4 + T细胞引发缺陷， 死亡率（J Exp Med.2007，204：2591-602）。为了调查运输机是否与 抗原处理（TAP）1是CD 8 + T细胞介导的弓形虫控制所必需的。 在体内，我们比较了TAP 1-/-、CD 8-/-和野生型（WT）小鼠对感染 寄生虫令人惊讶的是，TAP 1-/-小鼠显示出比CD 8-/-或 WT小鼠感染无毒力寄生虫株。电阻的降低 TAP 1-/-小鼠与活化和IFN-γ产生频率的降低相关。 CD 4 + T细胞。有趣的是，感染的TAP 1-/-小鼠显示IFN-γ的频率降低， 相对于WT对照产生自然杀伤（NK）细胞，并且在NK 细胞耗竭CD 8-/-和WT小鼠都死于感染，其动力学与 TAP 1-/-动物和显示受损的CD 4 +T细胞IFN-γ应答。这些结果一起 揭示了TAP 1在IFN-γ诱导中以前未被认识到的作用 产生NK细胞，并首次证明了 该细胞群在引发CD 4 + T淋巴细胞对T.弓形虫感染 这些研究现在正在扩展，以了解TAP 1-/-和 β 2微球蛋白-/-在NK细胞的这一功能中的作用以及NKT细胞在 NK活性的调节。肿瘤发生中的先天性抵抗和促炎细胞因子。 一个非常广泛的调查已经开始研究炎症受体的作用， 和细胞因子在皮肤和结肠化学致癌中的作用。根据我们早期的观察， MyD 88-/-对皮肤癌变具有抗性，我们现在已经表明，MyD 88的表达是 在抗辐射皮肤细胞以及造血细胞中都需要MyD 88-/- 角质形成细胞在Ras转化后其基因表达模式发生了很大的改变， 这表明，这种基因表达模式的改变可能是缺乏 化学致癌反应中息肉的形成。在结肠中，MyD 88缺乏症 导致对DSS诱导的结肠炎的易感性增加， 与对化学诱导的致癌作用的高度易感性相关。的 MyD 88表型的部分原因是缺乏通过IL-18受体的信号传导。 MyD 88细胞。我们还观察到TNF是结肠炎依赖性致癌作用所必需的 但有趣的是，肠上皮细胞产生的TNF是致癌所必需的，而T 产生TNF的细胞和巨噬细胞具有抗肿瘤作用。这些结果表明，TNF，a 分子最初被描述为具有抗肿瘤活性，但后来被描述为必需的 致癌因子，确实具有双重作用，其抗肿瘤和促肿瘤活性 取决于它是由哪些细胞产生的，可能还取决于不同细胞的瞬时产生 在致癌过程中。

Progress has been made in several of the aims of the project, in particular on the role of TLR signaling in regulating proliferation and survival of fibroblasts and dendritic cells, on the regulation of cytokine production from human DC, on the role of plasmacytoid DC in regulating oral tolerance, on the effect of NK cells on Th1 differentiation in Toxoplasma Gondii infection, role of TNF, MyD88 and IL-18 in colitis-dependent carcinogenesis. Hepatic plasmacytoid dendritic cells contribute to orally induced CD8+ T cell tolerance (Immunity. 2008; 9:464-75). The liver is thought to contribute to systemic T cell tolerance to orally absorbed antigens, although the precise mechanism of its tolerogenic effect is unclear. Here we show that the liver is a site of oral antigen presentation and that hepatic dendritic dells (DC) can tolerize mice to subsequent CD8+ T cell priming, in a model of hapten-specific contact sensitivity (CHS). The tolerogenic potential of liver DC is confined to plasmacytoid DC (pDC), is enhanced by exposure to hapten, and requires CD4+ T cells. Finally, in vivo depletion of pDC abrogated oral tolerance and restored hapten-specific CD8+ T cell and CHS responses. Thus, pDC are tolerogenic and play an essential role in oral tolerance. These studies are now being extended to analyze the role of liver pDC in other model of tolerance and in particular in testing whether pDC are require to induce TNBS tolerance in a model of colitis and carcinogenesis. We have generate a mouse expressing the human Dyptheria Toxin Receptor and the Green Fluorescent protein specifically on pDC. These mice can be used for the identication and in vivo depletion of pDC and they will be used in experiments aimed to identify and deplete pDCs in vivo. In addition to the models of oral tolerance we have established that TLR9-activated pDC in the intestinal lamina propria prevent the conversion of naive CD4 T cells in FoxP3+ Treg and we are estending our studies to other models in which pDCs are involved in immunoregulation. Toxoplasma gondii infected TAP1 deficient mice display impaired NK cell IFN-gamma production leading to defective CD4+ T cell priming and increased mortality (J Exp Med. 2007, 204:2591-602). To investigate if Transporter Associated with Antigen Processing (TAP)1 is required for CD8+ T cell mediated control of Toxoplasma gondii in vivo, we compared the resistance of TAP1-/-, CD8-/- and wild-type (WT) mice to infection with the parasite. Surprisingly TAP1-/- mice displayed greater susceptibility than either CD8-/- or WT mice to infection with an avirulent parasite strain. The decreased resistance of the TAP1-/- mice correlated with a reduction in the frequency of activated and IFN-gamma-producing CD4+ T cells. Interestingly, infected TAP1-/- mice showed a reduced frequency of IFN-gamma producing natural killer (NK) cells relative to that of WT controls, and after NK cell-depletion both CD8-/- and WT mice succumbed to infection with the same kinetics as TAP1-/- animals and displayed impaired CD4+T cell IFN-gamma responses. Together, these results reveal a previously unappreciated role for TAP1 in the induction of IFN-gamma producing NK cells and provide the first demonstration of the function of this cell population in the priming of CD4+ T lymphocyte responses to T. gondii infection. These studies are now being extended to understand the difference between the TAP1-/- and beta2microglobulin-/- in this function of NK cells and the possible role of NKT cells in the regulation of NK activity. Innate resistance and pro-inflammatory cytokines in carcinogenesis. A very extensive investigation has been initiated to study the role of inflammatory receptors and cytokines in skin and colon chemical carcinogenesis. Following our early observation that MyD88-/- are resistant to skin carcinogenesis, we have now showed that MyD88 expression is required both in radioresistant skin cells as well as in hematopoieitc cells and that MyD88-/- keratinocytes are very altered in their gene expression pattern after Ras transformation in vitro, suggesting that this altered pattern of gene expression may be responsible for the lack of polyps formation in response to chemical carcinogenesis. In the colon, MyD88 deficiency resulted in an increased susceptibility to DSS induced colitis that surprisingly was associated with a highly increased susceptibility to chemically induced carcinogenesis. The MyD88 phenotype was in part due to lack of signaling through the IL-18 receptor in the MyD88-/- cells. We also observed that TNF is required for colitis-dependent carcinogenesis but, interestingly, TNF produced by the enterocytes was required for carcinogenesis whereas T cells and macrophages produced TNF had an antitumor effect. These results indicate that TNF, a molecule described originally for its anti-tumor activity but then described as a required factor for carcinogenesis, has indeed a dual role and its anti-tumor and pro-tumor activity depend by which cells it is produced and probably by its temporal production by different cell types during the carcinogenesis processes.