This study showed that statins can reduce MMP expression in atheroma and that cell-permeant statins can decrease SMC number and collagen gene expression in vivo.

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We examined the effect of TGF-β1 on the chemotactic migratory ability of human monocyte-derived dendritic cells (DCs). Treatment of immature DCs with TGF-β1 resulted in increased expressions of CCR-1, CCR-3, CCR-5, CCR-6, and CXC chemokine receptor-4 (CXCR-4), which were concomitant with enhanced chemotactic migratory responses to their ligands, RANTES (for CCR-1, CCR-3, and CCR-5), macrophage-inflammatory protein-3α (MIP-3α) (for CCR-6), or stromal cell-derived growth factor-1α (for CXCR-4). Ligation by TNF-α resulted in down-modulation of cell surface expressions of CCR-1, CCR-3, CCR-5, CCR-6, and CXCR-4, and the chemotaxis for RANTES, MIP-3α, and stromal cell-derived growth factor-1α, whereas this stimulation up-regulated the expression of CCR-7 and the chemotactic ability for MIP-3β. Stimulation of mature DCs with TGF-β1 also enhanced TNF-α-induced down-regulation of the expressions of CCR-1, CCR-3, CCR-5, CCR-6, and CXCR-4, and chemotaxis to their respective ligands, while this stimulation suppressed TNF-α-induced expression of CCR-7 and chemotactic migratory ability to MIP-3β. Our findings suggest that TGF-β1 reversibly regulates chemotaxis of DCs via regulation of chemokine receptor expression.

We analyzed the expression of IL-12Rβ1 and IL-12Rβ2 and the role of IL-12 in the activation of monocyte-derived dendritic cells (DCs) via IL-12Rβ1-mediated signaling events. Flow cytometric analysis revealed that IL-12Rβ1 was expressed in T cells, Con A blasts, and monocyte-derived DCs, but not in monocytes, while its transcript was detected in all of these cell types. Transcriptional expression of IL-12Rβ2 was observed in T cells, Con A blasts, and monocyte-derived DCs, but not monocytes. The ligation of DCs as well as Con A blasts by IL-12 induced the production of GM-CSF, IL-1β, IL-6, TNF-α, and IFN-γ at the transcription levels. Furthermore, stimulation of DCs with IL-12 induced IL-12p40 transcript, but not IL-12p35 transcript, whereas this stimulation caused the expressions of both transcripts in Con A blasts. Stimulation of DCs with IL-12 caused a tyrosine phosphorylation of several intracellular proteins, and the pattern of these events were distinct from those of IL-12-stimulated Con A blasts. IL-12 also induced tyrosine phosphorylation of IL-12Rβ1 as well as recruitment of several tyrosine-phosphorylated proteins to IL-12Rβ1 in DCs and Con A blasts. Receptor engagement of DCs as well as Con A blasts by IL-12 resulted in activation of Janus kinase 2 and Tyk2 kinases and Stat3 and Stat4 transcription factors and the association of these proteins to IL-12Rβ1. Stimulation with IL-12 caused a tyrosine phosphorylation and enzymatic activity of a family of mitogen-activated protein kinases, p38mapk. These results suggest that IL-12 acts directly on DCs to induce their functional activation via IL-12Rβ1-mediated signaling events.

We conducted a pilot study to assess the feasibility and efficacy of immunotherapy for stage IV malignant melanoma patients resistant to conventional therapies involving vaccination with mature dendritic cells (mDCs) combined with administration of low dose interleukin-2. Autologous monocytes were harvested from a single apheresis and cultured for 7 days with granulocyte-macrophage colony-stimulating factor and interleukin-4, yielding immature dendritic cells (iDCs), which were then cryopreserved until use. For 4 days prior to vaccination, iDCs were exposed to autologous tumour lysate combined with tumour necrosis factor-alpha to induce terminal differentiation into mDCs. Patients were then vaccinated weekly with 107 mDCs for 10 weeks and given 350-700 kIU of interleukin-2 three times per week. Of the 10 patients in the study, one showed stable disease, seven showed progressive disease, and two showed mixed responses, including partial tumour regression, and were therefore given 20 additional injections. Only minimal adverse events were noted, including localized skin reactions and mild fever (NIH-CTC grade 0-1). Median survival from the first vaccination was 240 days (range 31-735 days). In vitro, melanoma patient-derived dendritic cells (DCs) showed reduced cell surface expression of CD1a antigen on iDCs and reduced CD86 and HLA-DR expression on mDCs. In addition, antigen uptake, chemotaxis and antigen presentation were all attenuated in DCs from the patients. In summary, although improvement of clinical efficacy will require further research, autologous tumour lysate-pulsed monocyte-derived mDCs could be safely harvested, cryopreserved and administrated to patients without obvious complications.

Chemokines and their receptors play a critical role in the selective attraction of various subsets of leukocytes. We examined the chemokine receptor expressions and responsiveness of cord blood (CB) T cells. Flow-cytometric analysis revealed that peripheral blood (PB) T cells expressed CCR-1, CCR-2, CCR-5, CCR-6, CXC chemokine receptor-3 (CXCR-3), and CXCR-4, while CB T cells expressed only CXCR-4 on their surface. Chemotactic migratory response of CB T cells to macrophage-inflammatory protein (MIP)-1α, monocyte chemoattractant protein-1, RANTES, MIP-3α, monokine induced by IFN-γ, and IFN-γ-inducible protein-10 was significantly impaired compared with those of PB T cells. In contrast, the ability of CB T cells to migrate to MIP-3β, 6Ckine, and stromal cell-derived factor-1α was greater than that of PB T cells, and these events were correlated with the expression levels of CCR-7 and CXCR-4, respectively. Engagement of CD3 and CD28 specifically up-regulated CXCR-3 expression and chemotaxis to monokine induced by IFN-γ and IFN-γ-inducible protein-10, whereas this stimulation down-regulated CCR-7 expression and chemotaxis to MIP-3β and 6Ckine in PB T cells, but not in CB T cells. These results suggest that PB T cells and CB T cells exhibit distinct chemokine responsiveness via different chemokine receptor repertoire.

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