Dendritic cells (DCs) are potent antigen-presenting cells that play a pivotal role in the initiation of T cell-dependent immune responses. Immature DCs obtained from peripheral blood CD14+ monocytes by culture with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) differentiate into mature DCs upon stimulation with lipopolysaccharide (LPS). At least three families of mitogen-activated protein kinases (MAPKs), that is, extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK) and p38 MAPK, are involved in the DC maturation process. We report investigations of the role of JNK in the maturation of human monocyte-derived DCs. SP600125, a specific inhibitor of JNK, inhibited the LPS-induced up-regulation of CD80, CD83, CD86 and CD54, but augmented the up-regulation of HLA-DR. SP600125 slightly inhibited the down-regulation of FITC-dextran uptake during DC maturation. However, SP600125 did not affect the LPS induced up-regulation of allostimulatory capacity of DCs. SP600125 inhibited the release of IL-12 p70 and TNF-alpha from mature DCs. Although autologous T cells primed by the ovalbumin (OVA)-pulsed mature DCs produced IFN-gamma, but not IL-4, OVA-pulsed SP600125-treated mature DCs could initiate IL-4 production from autologous T cells. In contrast, a p38 MAPK inhibitor, SB203580, profoundly inhibited the phenotypic and functional maturation of DCs, while an ERK inhibitor, PD98059, had little or no effect. Taken together, the JNK signaling pathway appears to have a role that is distinct from the p38 MAPK and ERK cascades in the maturation process of DCs, and may be involved in the augmentation of Th2-prone T cell responses when it is suppressed.

This protocol details a method of obtaining selectively proliferated hepatocyte progenitor cells using hyaluronic acid (HA)-coated dishes and serum-free medium. A small hepatocyte (SH) is a hepatocyte progenitor cell of adult livers and has many hepatic functions. When the rat SH begins to proliferate, CD44 is specifically expressed. To define the purification of SH, CD44 and cytokeratin 8 are used as marker proteins. The growth of SHs is faster on HA-coated dishes than on other extracellular matrix-coated ones. The use of both DMEM/F12 medium and HA-coated dishes allows the selective proliferation of SHs in culture. The purification of SHs is approximately 85% at day 10.

The complete and mild-condition fractionation of woody biomass without the energy-intensive size reduction still remains a significant challenge. This study reports an innovative and scalable cellulose-centred fractionation process based on...

In galactosamine (GalN)-induced rat liver injury, hepatic stem/progenitor cells, small hepatocytes (SHs) and oval cells, transiently appear in the initial period of liver regeneration.

CD44highCD8 T cells in naive mice, which increase with age, and are often referred to as memory CD8 T cells. However, since thymus‐independent CD8 T cells have also been shown to be CD44high, the origin of the CD44highCD8 T cells in naive mice remains unclear. In this study, we compared the characteristics of memory CD8 T cells and thymus‐independent CD8 T cells in TCR transgenic mice to clarify the origin of the CD44highCD8 T cells in naive normal mice. The memory and thymus‐independent CD8 T cells showed differences in surface molecules, spontaneous cell death, cytokine production, and response to IL‐2R binding of cytokines. Importantly, the "memory phenotype" CD8 T cells in naive normal mice showed similar characteristics to the thymus‐independent CD8 T cells, but differed greatly from "true" memory CD8 T cells in the TCR transgenic mice. Therefore, we conclude that a significant part of the CD44high memory phenotype CD8 Tcells in naive normal mice represents thymus‐independent CD8 T cells, which may participate in age‐related changes in immune responses.

Rat small hepatocytes (SHs) are committed progenitor cells that can differentiate into mature hepatocytes and can selectively proliferate in serum-free medium when they are cultured on hyaluronic acid (HA)-coated dishes. In this study we examined the separation of human SHs from adult human livers. We obtained liver tissues from the resected liver of 16 patients who underwent hepatic resections. Extracted liver specimens were clearly separate from the tumor regions with sufficient margins. Hepatic cells were isolated using the modified method of two-step collagenase perfusion. A low-speed centrifugation was performed and cells in the supernatant were finally cultured on HA-coated dishes in serum-free DMEM/F12 medium including nicotinamide, EGF, and HGF. Small-sized hepatocytes selectively proliferated to form colonies and many colonies continued growing for more than 3 weeks. The average number of cells in a colony was 38.6 +/- 18.0, 79.0 +/- 54.0, and 101.5 +/- 115.7 at day 7, 14, and 21, respectively. About 0.04% of plated cells could form an SH colony. Immunocytochemistry showed that the cells forming a colony were positive for albumin, transferrin, keratin 8, and CD44. The results of RT-PCR showed that colony-forming cells expressed albumin, transferrin, alpha1-antitrypsin, fibrinogen, glutamine synthetase, many cytochrome P450s, and liver-enriched transcription factors (HNF3alpha, HNF4alpha, C/EBPalpha, and C/EBPbeta). Furthermore, the cells expressed not only the genes of hepatic differentiated functions but also those of both hepatic stem cell marker (Thy1.1, EpCAM, AFP) and SH marker (CD44, D6.1A, BRI3). Albumin secretion into culture medium was also observed. Our results demonstrate the existence of hepatocyte progenitor cells in human adult livers, and the cells can grow in a serum-free medium on HA-coated dishes. Human SHs may be a useful source for cell transplantation as well as pharmaceutical and toxicological investigations.

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