| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2002: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
In type I diabetes mellitus, dendritic cells play pivotal roles ; they retain capacity to activate autoreactive T cells in the periphery, but are unable to process and/ or resent autoantigens in a tolerogenic fashion. Abnormal phenotype and function of DC from NOD mice have been reported. To characterize molecular changes in Cd11c^+ bone marrow-derived DC from NOD mice, we recently compared the transcript profiles of these cells with those from NON mice. DC from NOD showed 8-fold reduced interleukin 6 (IL-6) mRNA expression compared to those from NON mice. In this study, we examined IL-6 production by DC from NOD mice to confirm the decreased production of this cytokine at protein level. Effect by IL-6 supplementation during differentiation on the phenotype and function of DC was also investigated.
Bone marrow cells from 4-week-old female mice were cultivated in the presence of GM-CSF and IL-4 over 6 days, with or without IL-6 supplementation. CD11c^+ DC were sorted by magnetic beads-conjugated with anti-CD11c antibodies (MACS^<TM>).
DC from NOD produced significantly lower amount of IL-6 in response to 5 mg/ ml LPS (10970±1685.0 pg/ml) than those from NON (45845±3506.6 pg/ml, p<0.05, Mann-Whitney U test). DC from NOD generated with additional IL-6 (2ng/ml) elicited significantly higher response by CD4^+ cells in the syngeneic mixed lymphocyte reaction (SMLR), measured by succinate-tetrazolium reductase activity (WST-1^<TM>), than those without IL-6 (optic density 0.36±0.031 vs 0.23±0.027, stimulator : responder ratio=1:20,p< 0.05). The up-regulated SMLR was associated with increased median fluorescent intensity of CD80 and CD86 expression by DC (CD80, 116±4.39 vs 92.1±2.75, p<0.05; CD86, 13.2±1.50 vs 9.77±0.289,p<0.05), and significantly lower IFNg production in the SMLR (412.1±40.94 vs 1639±131.6pg/ml,p<0.05).
Reduced autocrine secretion of IL-6 by DC may lead to defective phenotype and function of DC, and then to Th1-deviated immune reaction in NOD mice.
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