During 'emergency' situations such as infections, host defense requires rapid mobilization of bone marrow granulocyte progenitors. 'Steady-state' granulopoiesis is absolutely dependent on the C/EBPalpha transcription factor, but the transcriptional mechanisms underlying emergency granulopoiesis remain unclear. Here we show that large numbers of granulocytes were generated from C/EBPalpha-deficient progenitors after cytokine stimulation in vivo. Cytokine treatment or fungal infection induced upregulation of C/EBPbeta but not C/EBPalpha or C/EBPepsilon transcripts in granulocyte progenitors, and C/EBPbeta-deficient progenitors showed decreased emergency-induced granulopoiesis in vitro and in vivo. C/EBPbeta inhibited proliferation less severely than did C/EBPalpha. These data suggest a critical function for C/EBPbeta in emergency granulopoiesis, which demands both differentiation and proliferation of granulocyte precursors.

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Background-Helicobacter pylori strains possessing the cagA gene are thought to induce interleukin 8 (IL-8) in gastric mucosa. However, it is still unclear whether a relation exists between the cagA gene and the expression patterns of cytokines other than IL-8. Aims-To investigate the relation between the cagA gene and the production of various cytokine proteins using an enzyme linked immunosorbent assay (ELISA). Patients and methods-In 184 patients, the cagA gene was detected by polymerase chain reaction (PCR), and levels of production of IL-1 , IL-6, IL-7, IL-8, IL-10, and tumour necrosis factor (TNF-) in antral biopsy specimens were measured by ELISA. Results-Mucosal levels of IL-1 , IL-6, IL-8, and TNF-were significantly higher in H pylori positive than in H pylori negative patients. Furthermore, the mucosal levels of IL-1 and IL-8 were significantly higher in specimens infected with cagA positive strains than in those infected with cagA negative strains. In H pylori positive patients, the mucosal level of IL-8 was closely correlated with that of IL-1 (p<0.0001), and the mucosal level of IL-6 was closely correlated with that of TNF-(p<0.0001). Conclusion-These findings suggest that the ability to induce cytokines diVers among the strains; cagA + strains induce various kinds of cytokines and may cause severe inflammation, whereas cagA − strains induce IL-8 and IL-1 only weakly and may cause only mild inflammation. However, as most patients infected with the cagA + strains have gastritis, these strains may not be equivalent to ulcerogenic strains. (Gut 1997; 41: 442-451)

Cytokines may be crucially involved in the pathogenesis of inflammatory bowel diseases (IBD), but it remains controversial whether interferon (IFN)-gamma, a typical proinflammatory cytokine, is an essential mediator to cause the disorders. In the present study, IFN-gamma(-/-) and wild-type (WT) C57BL/6 mice were fed 2.5% dextran sodium sulphate (DSS) in drinking water for 7 days, in order to investigate DSS-induced intestinal inflammation. The DSS-treated WT mice exhibited a robust production of IFN-gamma in the gut, a remarkable loss of body weight, as well as high rate of mortality (60%). In striking contrast, IFN-gamma deficient mice did not develop DSS-induced colitis, as indicated by the maintenance of body weight and survival rate of 100%. Severe intestinal inflammation was demonstrated exclusively in WT animals in terms of the shortening of the bowel as well as the elevation of the disease activity index, myeloperoxidase (MPO) activity and serum haptoglobin level. Histological study of DSS-treated WT intestine revealed disruption of mucosal epithelium and massive infiltration of inflammatory cells, while the organ from IFN-gamma(-/-) mice remained virtually normal in appearance. Enzyme-linked immunosorbent assay (ELISA) analyses indicated abundant production of three chemokines, i.e. monokine induced by interferon-gamma (MIG), interferon-inducible protein 10 (IP-10) and monocyte chemoattractant protein-1 (MCP-1), in the DSS-irritated intestine of WT but not of IFN-gamma(-/-) mice. The present results demonstrate clearly that IFN-gamma plays indispensable roles in the initiation of DSS colitis, and some chemokines are produced in an IFN-gamma-dependent fashion.

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