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

树突状细胞（DC）在人类1型糖尿病、NOD小鼠和BB大鼠中表现出缺陷的功能和表型，并在该疾病的发病机制中起关键作用。为了研究NOD小鼠骨髓来源DC的分子变化，我们比较了NOD小鼠和NON小鼠骨髓来源DC的转录谱，发现NOD小鼠骨髓来源DC表达CD 204的水平显著高于NON小鼠。有趣的是，据报道DC上的CD 204介导从活细胞捕获抗原的能力，称为蚕食。CD 204在NOD DC上的强表达可能导致从自体细胞主动摄取抗原，然后导致自身免疫的易感性。针对这一点，我们在此研究了NOD来源的CD 204 ^+BM和脾DC的表型和功能。来自6周龄雌性小鼠的BM细胞在GM-CSF和IL-4存在下培养6天。CD 11 c ^+DC通过磁珠结合的抗CD 11 c抗体分选。通过流式细胞仪对DC进行表型分析。NOD系BMDC的CD 204平均荧光强度是正常系的7倍（NOD65.7 ±3.4，NON 8.2±0.34，C3 H/HeN 8.0±0.55，Balb/c 9.0±0.49 ; P<0.05，Mann-Whitney U检验）。在脾细胞中，NOD来源的CD 204 ^+ CD 11 c ^+ DC的比例显著高于正常株（NOD 0.65± 0.09%，NON 0.10± 0.02%，C3 H/HeN 0.10± 0.02%，Balb/c 0.04±0.03% ; p<0.05）。CD 204 ^+ CD 11 c ^+ BM和脾DC的表型为CD 4 ^<low>CD 8 ^-CD 11b ^<low>CD 16/32^+ CD 19 ^<low>CD 80 ^<high>CD 86 ^<high>MHCclassI^+classII^+F4/80^+Gr-1^<low>。NOD来源的未标记BMDC比NON来源的DC更快地获得其他细胞的荧光双标记膜，我们认为NOD来源的DC中一个独特的亚群中CD 204的高表达可能导致NOD DC对自身抗原的主动摄取，从而导致NOD DC易患自身免疫性疾病。

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.