Augstein P, Stephens L A, Allison J, Elefanty A G, Ekberg M, Kay T W, Harrison L C
Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Parkville, Victoria, Australia.
Mol Med. 1998 Aug;4(8):495-501.
The non-obese diabetic (NOD) mouse is a model of human type 1 diabetes in which autoreactive T cells mediate destruction of pancreatic islet beta cells. Although known to be triggered by cytotoxic T cells, apoptosis has not been unequivocally localized to beta cells in spontaneously diabetic NOD mice. We created a model of accelerated beta-cell destruction mediated by T cells from spontaneously diabetic NOD mice to facilitate the direct detection of apoptosis in beta cells.
NOD.scid (severe combined immunodeficiency) mice were crossed with bm1 mice transgenically expressing the costimulatory molecule B7-1 (CD80) in their beta cells, to generate B7-1 NOD.scid mice. Apoptosis in islet cells was measured as DNA strand breakage by the TdT-mediated-dUTP-nick end labeling (TUNEL) technique.
Adoptive transfer of splenocytes from spontaneously diabetic NOD mice into B7-1 NOD.scid mice caused diabetes in recipients within 12-16 days. Mononuclear cell infiltration and apoptosis were significantly greater in the islets of B7-1 NOD.scid mice than in nontransgenic NOD.scid mice. Dual immunolabeling for TUNEL and either B-7 or insulin, or the T cell markers CD4 and CD8, and colocalization by confocal microscopy clearly demonstrated apoptosis in beta cells as well in a relatively larger number of infiltrating T cells. The clearance time of apoptotic beta cells was estimated to be less than 6 min.
B7-1 transgenic beta cells undergo apoptosis during their accelerated destruction in response to NOD mouse effector T cells. Rapid clearance implies that beta cells undergoing apoptosis would be detected only rarely during more protracted disease in spontaneously diabetic NOD mice.
非肥胖糖尿病（NOD）小鼠是人类1型糖尿病的模型，其中自身反应性T细胞介导胰岛β细胞的破坏。尽管已知细胞毒性T细胞会引发细胞凋亡，但在自发糖尿病的NOD小鼠中，细胞凋亡尚未明确定位于β细胞。我们创建了一个由自发糖尿病NOD小鼠的T细胞介导的加速β细胞破坏模型，以促进直接检测β细胞中的细胞凋亡。
将NOD.scid（严重联合免疫缺陷）小鼠与在其β细胞中转基因表达共刺激分子B7-1（CD80）的bm1小鼠杂交，以产生B7-1 NOD.scid小鼠。通过TdT介导的dUTP缺口末端标记（TUNEL）技术，将胰岛细胞中的细胞凋亡测量为DNA链断裂。
将自发糖尿病NOD小鼠的脾细胞过继转移到B7-1 NOD.scid小鼠中，在12-16天内使受体发生糖尿病。B7-1 NOD.scid小鼠胰岛中的单核细胞浸润和细胞凋亡明显高于非转基因NOD.scid小鼠。对TUNEL与B-7或胰岛素，或T细胞标志物CD4和CD8进行双重免疫标记，并通过共聚焦显微镜进行共定位，清楚地证明了β细胞以及相对大量浸润T细胞中的细胞凋亡。凋亡β细胞的清除时间估计少于6分钟。
B7-1转基因β细胞在响应NOD小鼠效应T细胞的加速破坏过程中发生凋亡。快速清除意味着在自发糖尿病NOD小鼠的更长期疾病过程中，很少能检测到正在发生凋亡的β细胞。
