A unique CD204^+ subpopulation of dendritic cells in NOD mice

树突状细胞（DC）在人类1型糖尿病以及NOD小鼠和BB大鼠中表现出功能和表型缺陷，并在该疾病的发病机制中发挥关键作用。为了表征NOD小鼠骨髓（BM）来源DC的分子变化，我们将这些细胞的转录谱与NON小鼠的转录谱进行了比较，然后发现NOD小鼠BMDC表达的CD204水平明显高于NON小鼠。有趣的是，据报道DC上的CD204介导了一种从活细胞中捕获抗原的能力，这种能力被称为“啃噬”。CD204在NOD DC上的强表达可能导致自体细胞对抗原的主动摄取，从而导致自身免疫的易感性。针对这一点，我们在此研究了NOD的CD204^+BM和脾DC的表型和功能。6周龄雌性小鼠BM细胞在GM-CSF和IL-4存在下培养6天。CD11c^+DC采用磁珠偶联抗CD11c抗体进行分选。流式细胞仪对DC进行表型分析。通过监测DiO标记、did标记和未标记细胞之间质膜的运输来评估BMDC的咬噬作用。NOD BMDC的CD204平均荧光强度比正常菌株高7倍（NOD 65.7±3.4,NON 8.2±0.34,C3H/HeN 8.0±0.55,Balb/c 9.0±0.49；P<0.05， Mann-Whitney U检验）。脾细胞中来自NOD的CD204^+CD11c^+ DC比例显著高于正常株（NOD 0.65±0.09%,NON 0.10±0.02%,C3H/HeN 0.10±0.02%,Balb/c 0.04±0.03%,p<0.05）。CD204^+CDllc^+ BM和脾DC的表型为CD4^<低>CD8^-CD11b^<低>CD16/32^+CD19^<低>CD80^<高>CD86^<高>MHCclassI^+classII^+F4/80^+Gr-1^<低>。来自NOD的未标记BMDC比来自NON的BMDC更快地从其他细胞获得荧光双标记膜。我们认为，CD204在NOD DC的一个独特亚群中高表达，可能导致NOD对自身抗原的主动摄取，从而导致自身免疫性疾病的易感性。

Dendritic cells (DC) display defective function and phenotype in human type 1 diabetes, as well as in NOD mice and BB rats, and play crucial roles in the pathogenesis of this disease. To characterise molecular changes in bone marrow (BM)-derived DC from NOD, we compared transcript profiles of these cells with those from NON mice, and then found that BMDC from NOD express significantly higher level of CD204 than NON. Interestingly, CD204 on DC reportedly mediates a capacity to capture antigens from live cells referred to as nibbling. Strong expression of CD204 on NOD DC possibly leads to active antigen uptake from autologous cells, and then to the predisposition to autoimmunity. Focusing on this point, we here investigated the phenotype and function of CD204^+BM and splenic DC from NOD.BM cells from 6-week-old female mice were cultivated in the presence of GM-CSF and IL-4 over 6 days. CD11c^+DC were sorted by magnetic beads-conjugated anti-CD11c antibodies. DC were phenotyped by a flow cytometer. Nibbling by BMDC was evaluated by monitoring the trafficking of plasma membrane between DiO- and DiD-labeled and unlabeled cells.BMDC from NOD displayed 7 times higher mean fluorescence intensity of CD204, than normal strains (NOD 65.7±3.4, NON 8.2±0.34, C3H/HeN 8.0±0.55, Balb/c 9.0±0.49 ; P<0.05, Mann-Whitney U test). Among splenocytes, the proportion of CD204^+CD11c^+ DC from NOD was significantly higher than normal strains (NOD 0.65±0.09%, NON 0.10±0.02%, C3H/HeN 0.10± 0.02%, Balb/c 0.04±0.03% ; p<0.05). The phenotypes of CD204^+CDllc^+ BM and splenic DC were CD4^<low>CD8^-CD11b^<low>CD16/32^+CD19^<low>CD80^<high>CD86^<high>MHCclassI^+classII^+F4/80^+Gr-1^<low>. Unlabeled BMDC from NOD acquired fluorescently dual labeled membrane from other cells more rapidly than those from NON.We propose that CD204 highly expressed in a unique subpopulation of DC from NOD possibly leads to active uptake of self-antigens, and then to the predisposition to autoimmune diseases in NOD.