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The mRNA of the ubiquitin-like modifier FAT10 has been reported to be overexpressed in 90% of hepatocellular carcinoma (HCC) and in over 80% of colon, ovary and uterus carcinomas. Elevated FAT10 expression in malignancies was attributed to transcriptional upregulation upon the loss of p53. Moreover, FAT10 induced chromosome instability in long-term in vitro culture, which led to the hypothesis that FAT10 might be involved in carcinogenesis. In this study we show that interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha synergistically upregulated FAT10 expression in liver and colon cancer cells 10- to 100-fold. Real-time RT-PCR revealed that FAT10 mRNA was significantly overexpressed in 37 of 51 (72%) of human HCC samples and in 8 of 15 (53%) of human colon carcinomas. The FAT10 cDNA sequences in HCC samples were not mutated and intact FAT10 protein was detectable. FAT10 expression in both cancer tissues correlated with expression of the IFN-gamma- and TNF-alpha-dependent proteasome subunit LMP2 strongly suggesting that proinflammatory cytokines caused the joint overexpression of FAT10 and LMP2. NIH3T3 transformation assays revealed that FAT10 had no transforming capability. Taken together, FAT10 qualifies as a marker for an interferon response in HCC and colon carcinoma but is not significantly overexpressed in cancers lacking a proinflammatory environment.

T-cell activation and local cytokine production probably contribute to the pathogenesis of Crohn's disease. This study investigates the proliferative status of intestinal mononuclear cells (MNC) and cytokine messenger RNA (mRNA) production in gut tissue sections from patients with Crohn's disease and noninflamed controls. mRNA in situ hybridization was performed using 33P-labelled riboprobes for human interleukin (IL)-1 beta, IL-2, IL-4, IL-5, IL-6, tumour necrosis factor-alpha and interferon-gamma. The expression of the proliferation-associated antigen Ki-67 was analysed by immunohistochemical single and double staining. Compared with controls, where proliferation of MNC and cytokine expression was restricted to mucosal lymphoid follicles, inflamed gut tissue contained increased numbers of cells expressing cytokine mRNA, most prominently IL-1 beta and IL-6, but also interferon-gamma and tumour necrosis factor-alpha. Proliferating T-cells were increased in number, and small amounts of IL-2-expressing cells were detected. IL-4 was expressed by a few cells exclusively in follicular germinal centres. IL-5 was negative. Proinflammatory cytokines are strongly expressed in situ in Crohn's disease and largely predominate over lymphokine mRNA. Our results provide in situ evidence of a local lymphocyte response in Crohn's disease with characteristics of a delayed-type hypersensitivity reaction.

Adhesion molecules such as CD2 and its ligand CD58 (LFA-3), as well as CD11a/18 (LFA-1) and CD54 (ICAM-1) regulate not only cell to cell attachment but also participate in lymphocyte activation, recirculation, and effector function including cytolytic activity towards tumor cells. We have investigated the role of CD2/CD58 and CD11a/18/CD54 interactions in cellular immune responses directed towards freshly recovered human T cell leukemias. Downregulation of CD54 and CD58 were observed to correlate with enhanced numbers of blasts in circulation and lack of susceptibility to killing by autologous cytotoxic lymphocytes. Furthermore, culturing tumor cells with recombinant TNF-alpha conditioned medium resulted in reinduction of CD54 and CD58 expression and susceptibility to lymphocyte mediated resulted in reinduction of CD54 and CD58 expression and susceptibility to lymphocyte mediated lysis in vitro. Our findings support the view that adhesion molecules play a pivotal role for tumor cell biology in vivo and stress the point that successful immunotherapy of malignant disease may be facilitated by influencing not only the immune response itself but also adhesion molecules on the malignant tumor targets.

Human intestinal lamina propria T lymphocytes (LPT), when investigated ex vivo, exhibit functional properties profoundly different from those of peripheral blood T lymphocytes (PBT). One prominent feature represents their enhanced sensitivity to CD2 stimulation when compared to PBT. Given that LPT are hyporesponsive to T cell receptor (TCR)/CD3 stimulation, an alternative activation mode, as mimicked by CD2 triggering in vitro, may be functional in mucosal inflammation in vivo. This study provides insight into signalling events associated with the high CD2 responsiveness of LPT. When compared to PBT, LPT show an increased activation of the phosphoinositide 3/protein kinase B/glycogen synthase kinase 3β (PI3-kinase/AKT/GSK-3β) pathway in response to CD2 stimulation. Evidence is provided that up-regulation of this pathway contributes to the enhanced CD2-induced cytokine production in LPT. Given the importance of TCR-independent stimulation for the initiation of intestinal immune responses analysis of signalling pathways induced by ‘co-stimulatory’ receptors may provide valuable information for therapeutic drug design. [ABSTRACT FROM AUTHOR]

Background and aims: Erroneous thymic selection of developing T lymphocytes may be responsible for the expansion of self reactive T cells or may contribute to the absence of regulatory T cells important in controlling peripheral inflammatory processes. Colitis in bone marrow (BM) transplanted Tg∊26 mice is induced by abnormally activated T cells developing in an aberrant thymic microenvironment. We investigated the protective role of regulatory CD4+CD25+ T cells in this model. Methods: BM from (C57B1/6 × CBA/J) F1 mice was transplanted into specific pathogen free Tg∊26 mice (BM→Tg∊26). Transplanted mice received no cells (control), sorted CD4+CD25+, or CD4+CD25+ cells from mesenteric lymph nodes (MLN) of normal mice. MLN cell subsets were analysed using membrane markers. Cytokine secretion of MIN cells was measured using intracellular cytokine staining and cytokine secretion in anti-CD3 stimulated cell cultures. Colitis was measured by histological scores. Results: CD4+CD25- cells were reduced in the MINs of BM=→Tg∊26 mice. Transfer of regulatory CD4+CD25+ but not of CD4+CD25+ cells reduced the number of MIN CD4+ T cells in BM=→Tg∊26 recipients and increased the number of MLN CD8+ cells, thereby normalising the CDt/CD8+ ratio. CD4+CD25+ but not CD4+CD25+ cell transfer into BM=→Tg∊26 mice reduced the number of tumour necrosis factor α+ CD+ cells and increased the secretion of transforming growth factor β by MIN cells. Transfer of 3 × 105 CD4+CD25+ cells after BM transplantation into Tg∊26 mice prevented colitis whereas CD4+CD25+ cells had no protective effect. Conclusions: These results suggest that defective selection or induction of regulatory I cells in the abnormal thymus is responsible for the development of colitis in BM=→Tg∊26 mice. Transfer of CD4+CD25+ cells can control intestinal inflammation in BM=→Tg∊26 mice by normalising the number and function of the MIN T cell pool. [ABSTRACT FROM AUTHOR]

Background: The causes of Crohn disease (CD) are still regarded as unknown, but impaired mucosal immunoregulation with activation of T-helper-1 (Th-1) cytokine responses is probably involved and may contribute to the morphological changes. We investigated a possible role of osteopontin (Opn) in the pathogenesis of CD. This glycoprotein has been suggested to be involved in the generation of Th-1-type immune responses; moreover, it carries anti-inflammatory activities. Methods: Ileal samples from CD patients—both actively inflamed and inactive areas as well as unaffected intestinal specimens from controls (normal ileum)—were investigated by Western blot analysis, immunohistochemistry and in situ hybridization. Results: In normal gut, Opn was found to be regularly expressed by plasma cells (CD 38) and a subset of lamina propria mononuclear cells (MNC) as well as by intestinal epithelial cells (IEC). In active CD, immunohistochemistry and in situ hybridization analysis revealed a loss of Opn expression by IEC adjacent to ulcerative lesions, whereas especially plasma cells (CD 38) in the vicinity of such lesions were found to express the molecule. In addition, a slight overexpression of Opn protein was found in metaplastic crypts. However, quantitative analysis of total Opn protein in the ileal mucosa of CD patients did not reveal any difference vis-à-vis control tissues. Conclusions: The constitutive expression of Opn in normal gut indicates that it is involved in intestinal immune homeostasis. Downregulation of Opn expression in IEC might favour the disintegration of the epithelial barrier. The expression of Opn in lamina propria plasma cells could contribute to disease chronification, probably by affecting cell survival. [ABSTRACT FROM AUTHOR]

T-cell activation and local cytokine production probably contribute to the pathogenesis of Crohn's disease. This study investigates the proliferative status of intestinal mononuclear cells (MNC) and cytokine messenger RNA (mRNA) production in gut tissue sections from patients with Crohn's disease and noninflamed controls. mRNA in situ hybridization was performed using 33P-labelled riboprobes for human interleukin (IL)-1 beta, IL-2, IL-4, IL-5, IL-6, tumour necrosis factor-alpha and interferon-gamma. The expression of the proliferation-associated antigen Ki-67 was analysed by immunohistochemical single and double staining. Compared with controls, where proliferation of MNC and cytokine expression was restricted to mucosal lymphoid follicles, inflamed gut tissue contained increased numbers of cells expressing cytokine mRNA, most prominently IL-1 beta and IL-6, but also interferon-gamma and tumour necrosis factor-alpha. Proliferating T-cells were increased in number, and small amounts of IL-2-expressing cells were detected. IL-4 was expressed by a few cells exclusively in follicular germinal centres. IL-5 was negative. Proinflammatory cytokines are strongly expressed in situ in Crohn's disease and largely predominate over lymphokine mRNA. Our results provide in situ evidence of a local lymphocyte response in Crohn's disease with characteristics of a delayed-type hypersensitivity reaction. [ABSTRACT FROM AUTHOR]