Study of T cell activation mechanism

1)IL-1刺激引起的细胞内变化我们用Quin-2法研究了IL-1刺激后高表达人IL-2受体p55(Tac)的YT细胞胞内游离钙离子浓度的变化。细胞内游离钙浓度未见明显升高。然后，我们研究了IL-1刺激可能触发的LTB4、5-HETE和12-HETE的产生。然而，我们没有检测到此类代谢物的任何增加。IL-1加入后的花生四烯酸(可能来源于膜磷脂酰胆碱和磷脂酰乙醇胺)的测定也没有检测到任何变化。2)由单抗定义的两个新的T细胞活化相关抗原1)2H7抗原在刺激和长期培养的T细胞和一些表达IL-2受体但不表达静息外周血单核细胞的细胞系上表达。双色染色和流式细胞仪分析显示2H7抗原表达与IL-2受体(P55，Tac)表达相关。2H7抗体可抑制IL-2依赖的细胞增殖，但不能抑制TPA诱导的细胞增殖。提示2H7抗原是一种T细胞活化抗原，可能与IL-2/IL-2受体系统密切相关。2C2(HC22)抗原在17-21%的PHA刺激的外周血淋巴细胞上表达，但不表达静息淋巴细胞。在大多数ATL患者的白血病细胞上也检测到它。抗体免疫沉淀后的SDS-PAGE分析表明，2C2抗原的非分子质量约为16KD。本研究新开发的两株单抗将为T细胞活化机制的研究奠定基础。

1) Intracellular changes initiated by IL-1 stimulation.We studied the changes of intracellular free calcium concentration by Quin-2 method using YT cells which become to express higher number of p55(Tac) of human IL-2 receptor upon IL-1 addition. No significant increase in intracellular free calcium concentration was detected. Then, we studied the production of LTB4, 5-hete and 12-hete which might be triggered by IL-1 stimulation. However, we could not detect any increase of such metabolites. The measurement of arachidonic acid after IL-1 addition which may be derived from membrane phosphatidylcholine and phosphatidylethanolamine also failed to detect any changes.2) Two novel T cell activation-associated antigens defined by monoclonal antibodies.1) 2H7 antigen is expressed on stimulated and long-term cultured T cells and some cell lines expressing IL-2 receptor but not resting peripheral blood mononuclear cells. Two color staining followed by flowcytometric analysis revealed a correlation between 2H7 antigen expression and IL-2 receptor(p55,Tac) expression. 2H7 antibody inhibited IL-2 dependent cell proliferation but not TPA-induced cell proliferation. These results suggests that 2H7 antigen is a T cell activation antigen which may be closely associated with IL-2/IL-2 receptor system. 2) 2C2(HC22) antigen is expressed on 17-21% of PHA-stimulated peripheral blood lymphocytes but not resting lymphocytes. It is also detected on leukemic cells from the majority of patients with ATL. SDS-PAGE analysis following immunoprecipitation with the antibody showed that 2C2 antigen has an approximate nolecular weight of 16KD. These two monoclonal antibodies newly deceloped in the present study will be useful for the analysis of T cell activation mechanism.