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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Naked plasmid DNA (pDNA) and short interfering RNA (siRNA) duplexes were transduced into adult murine heart by means of sonoporation using the third-generation microbubble, BR14. Plasmid DNAs carrying luciferase, b-galactosidase (b-gal), or enhanced green fluorescent protein (EGFP) reporter genes were mixed with BR14 and injected percutaneously into the left ventricular (LV) cavity of C57BL/6 mice while exposed to transthoracic ultrasound at 1 MHz for 60 s. Sonoporation at an output intensity of 2.0 W/cm 2 and a 50% pulse duty ratio resulted in the highest luciferase expression in the heart. Histological examinations revealed significant expression of the b-gal and EGFP reporters in the subendocardial myocardium of LV. Intraventricular co-injection of siRNA-GFP and BR14 with concomitant ultrasonic exposure resulted in substantial reduction in EGFP expression in the coronary artery in EGFP transgenic mice. The present method may be applicable to gain-of-function and loss-of-function genetic engineering in vivo of adult murine heart.

Direct intratumoral transfection of cytokine genes was per-

Interleukin (IL)-27 is an IL-12 family cytokine playing a pivotal role in the induction of Th1 immune responses, although its action on natural killer (NK) cells has not been fully elucidated. Here, we show that IL-27 is capable of inducing phosphorylation of signal transducers and activators of transcription 1 and 3, as well as expression of T-bet and granzyme B in murine DX-5+ NK cells. IL-27 also enhances cytotoxic activity of NK cells both in vitro and in vivo, while the in vitro viability of NK cells is also improved by this cytokine. Therapeutic administration of the IL-27 gene drastically suppressed the growth of NK-unsusceptible SCCVII tumors that had been preestablished in syngenic mice, resulting in significant prolongation of the survival of the animals. This can likely be ascribed to the antibody-dependent cellular cytotoxicity machinery because IL-27 successfully induced tumor-specific IgG in the sera of the tumor-bearing mice, and supplementation of the sera enabled IL-27-activated NK cells to kill SCCVII cells in an Fc; receptor IIIdependent manner. These findings strongly suggest that IL-27 may offer a powerful immunotherapeutic tool to eradicate head and neck squamous cell carcinoma and other poorly immunogenic neoplasms through activating NK cells and inducing tumor-specific immunoglobulin that may cooperatively elicit antibody-dependent cellular cytotoxicity activity.