The levels of blastogenesis in allogeneic MLR containing T cells from one normal volunteer and irradiated dendritic cells from 29 patients with PBC, 17 patients with chronic hepatitis type C (CH-C) and 22 allogeneic normal controls were compared to see if there is any role of antigen-presenting cells (APC) in the pathogenesis of PBC. The stimulatory capacity of dendritic cells from PBC was significantly lower compared with that of dendritic cells from CH-C (P < 0.05) and normal controls (P < 0.05), which could not be attributable either to the levels of expression of surface molecules, such as HLA-DR and CD86 on dendritic cells, or to the levels of cytokines, such as IL-10 and IL-12. Significantly higher levels of NO were seen in the allogeneic MLR supernatants containing dendritic cells from PBC compared with the supernatants from cultures containing dendritic cells from CH-C (P < 0.001) or normal controls (P < 0.001). Moreover, dendritic cells from PBC produced 10 times more NO compared with dendritic cells from CH-C and normal controls (21.9 +/- 2.8 microM versus 1.6 +/- 0.3 microM and 1.6 +/- 0.3 microM, respectively; P < 0.001). The addition of N(G)-monomethyl-L-arginine monoacetate (L-NMMA), a known inhibitor of NO in allogeneic MLR containing dendritic cells from PBC, resulted in a significant decrease of NO and increase of blastogenesis. The selective impairment of dendritic cell function, increased production of NO by dendritic cells and restoration of blastogenesis using NO inhibitor in PBC have suggested a role for NO and dysfunction of dendritic cells in the pathogenesis of PBC. This inspires optimism that modulating the function of dendritic cells and controlling NO production, an improved therapeutic approach, might be planned for PBC.

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When mice were exposed to restraint stress for 12 or 24 h, severe lymphopenia was induced in all immune system organs, including the liver and the thymus. However, in adrenalectomized mice, this response was completely absent. Phenotypic characterization revealed that interleukin (IL)-2Rbeta+CD3int cells (i.e. extrathymic T cells) with CD4+ phenotype and the NK1.1+ subset of CD3int cells (i.e. NKT cells) in the liver as well as the mature conventional T cells in the thymus were resistant to such stress. In adrenalectomized mice, there was no significant change in the distribution of lymphocyte subsets in all tested organs before stress. Interestingly, the number of lymphocytes in the liver and spleen and the proportion of NKT cells in the liver rather increased after stress in these adrenalectomized mice. Therefore, endogenous steroid hormones were indicated to be important in the induction of immunosuppressive states after stress. Among stress associated cytokines, the secretion of tumour necrosis factor (TNF)-alpha was completely suppressed while that of IL-6 was partially suppressed in adrenalectomized mice. These results suggest that endogenous steroid hormones are important for the induction of the stress associated immunosuppression and that NKT cells are resistant to stress, namely, resistant to exposure to endogenous steroid hormones.

Lodging has been a major roadblock to attaining increased crop productivity. In an attempt to understand the mechanism for culm strength in rice, we isolated an effective quantitative trait loci (QTL), STRONG CULM3 (SCM3), the causal gene of which is identical to rice TEOSINTE BRANCHED1 (OsTB1), a gene previously reported to positively control strigolactone (SL) signaling. A near-isogenic line (NIL) carrying SCM3 showed enhanced culm strength and increased spikelet number despite the expected decrease in tiller number, indicating that SL also has a positive role in enhancing culm strength and spikelet number. We produced a pyramiding line carrying SCM3 and SCM2, another QTL encoding APO1 involved in panicle development. The NIL-SCM2+SCM3 showed a much stronger culm than NIL-SCM2 and NIL-SCM3 and an increased spikelet number caused by the additive effect of these QTLs. We discuss the importance of utilizing suitable alleles of these STRONG CULM QTLs without inducing detrimental traits for breeding.