Sordi V, Lampasona V, Cainarca S, Bonifacio E
Department of Medicine 1, San Raffaele Scientific Institute, Milan, Italy.
Diabet Med. 2005 Dec;22(12):1770-3. doi: 10.1111/j.1464-5491.2005.01756.x.
AIMS/HYPOTHESIS: Autoantibodies to the ADP ribosyl cyclase/cyclic ADP-ribose hydrolase CD38 have been suggested to be markers of autoimmunity in Type 1 and Type 2 diabetes. The aim of this study was to develop a fluid phase assay for population screening.
Human recombinant CD38 was cloned and expressed by in vitro transcription and translation for fluid phase radio-binding assay, as a fusion protein in COS7 cells for fluid phase immunoprecipitation, and as a fusion protein for western blot assays. Antibody binding to each recombinant protein was measured in sera from patients with Type 1 diabetes, Type 2 diabetes and control subjects.
Immunoprecipitation of radio-labelled in vitro transcribed and translated CD38 was low in all sera, including monoclonal anti-CD38 antibodies, with no difference between patients and control subjects. Monoclonal antibodies to CD38, but not patient or control sera immunoprecipitated recombinant CD38 fusion protein expressed in COS7 cells. Antibody binding to recombinant CD38 in solid-phase western blot assay was detected in sera from 2% of patients with Type 1 diabetes, 6% of patients with Type 2 diabetes, and 8% of control subjects.
This study failed to detect diabetes relevant binding of antibodies to recombinant CD38 using liquid-phase methods. Formal comparison of anti-CD38 antibody detection between laboratories is suggested.
目的/假设：1型和2型糖尿病中，针对ADP核糖基环化酶/环ADP核糖水解酶CD38的自身抗体被认为是自身免疫的标志物。本研究的目的是开发一种用于人群筛查的液相检测方法。
克隆人重组CD38，并通过体外转录和翻译进行表达，用于液相放射结合测定；作为融合蛋白在COS7细胞中表达，用于液相免疫沉淀；作为融合蛋白用于蛋白质印迹分析。在1型糖尿病患者、2型糖尿病患者和对照受试者的血清中检测抗体与每种重组蛋白的结合情况。
在所有血清中，包括单克隆抗CD38抗体，放射性标记的体外转录和翻译的CD38的免疫沉淀率都很低，患者和对照受试者之间没有差异。抗CD38单克隆抗体可免疫沉淀COS7细胞中表达的重组CD38融合蛋白，但患者或对照血清不能。在固相蛋白质印迹分析中，1型糖尿病患者血清中2%、2型糖尿病患者血清中6%以及对照受试者血清中8%检测到抗体与重组CD38结合。
本研究未能使用液相方法检测到抗体与重组CD38的糖尿病相关结合。建议各实验室对抗CD38抗体检测进行正式比较。
