人T细胞系Jurkat表达特异性的C1q受体

Human T Lymphocyte Line Jurkat Cells Express Specific Receptors for C1q

采用酶联免疫吸附试验、流式细胞术、放射配体结合试验及蛋白质印迹等方法，首次证实了人Ｔ细胞系Ｊｕｒｋａｔ表达特异性Ｃ１ｑ受体，并对其特性进行了分析Ｊｕｒｋａｔ可为Ｃ１ｑ或抗人Ｃ１ｑ受体抗体１１２识别，其对异硫氰酸荧光黄标记Ｃ１ｑ的结合能被未标记Ｃ１ｑ所抑制．在生理离子强度和温度条件下，Ｊｕｒｋａｔ与１２５Ｉ－Ｃ１ｑ的结合呈持异、剂量依赖、可饱和及可逆性，每个细胞Ｃ１ｑ结合位点数为１．１×１０６，对Ｃ１ｑ的Ｋａ值为１．５×１０７ｍｏｌ－１，Ｈｉｌｌ系数为０．９６４３．ＪｕｒｋａｔＣ１ｑ受体识别Ｃ１ｑ的胶原样区．

The C1q receptor (C1qR) on the human T lymphocyte line Jurkat cells was demonstrated and characterized. Cell-ELISA showed that Jurkat cells are able to bind exogenous C1q and recognized by the anti-C1qRantibody 112. FCM analysis indicated that the binding of FITC-C1q to Jurkat cells is blocked by an excess of unlabelled C1q.Quantitative binding studies with monomeric 125 I-C1q showed a specific, dose-dependent,saturable and reversible binding involving specific membrane receptors on Jurkat cells, Goldstein analysis and Hill plot of C1q binding showed 1. 1 × 106 binding sites per cell with an average affinity of 1. 5 ×107 mol-1and a Hill number of 0.9643 at normal ionic strength (I = 0. 15 ) and temperature (37℃).The experiment with the anti-C1q monoclonal antibody A4, which recognizes the collagen-like region (CLR) of C1q, established that it is via its CLR that C1q binds to Jurkat cell receptors.Western blotting with the anti-C1qR antibody 112 revealed that the C1qR on Jurkat cells is a membrane protein of 70 ku.