Christensen L D, Andersen V, Ryder L
Department of Infectious Diseases, National University Hospital, Copenhagen, Denmark.
Scand J Immunol. 1996 Jul;44(1):62-70. doi: 10.1046/j.1365-3083.1996.d01-281.x.
CD73 is a bifunctional glycosyl phosphatidylinositol anchored leucocyte differentiation antigen which has specific ecto-5'-nucleotidase (ecto-5'-NT) activity and is an accessory T-lymphocyte activation molecule. The aim of the present study was to investigate the CD73 expression on blood mononuclear cells (BMC) from a group of patients with primary immunoglobulin deficiency (IGD). This group of patients had both significantly decreased levels of ecto-5'-NT on BMC (P = 0.002) and decreased numbers of CD73 molecules per CD73+ lymphocyte (P = 0.01). Five of the 10 patients had a decreased percentage of CD73+ lymphocytes. Among B-lymphocytes the patients had normal percentages of CD73+ cells but four of the 10 patients had numbers of CD73 molecules per CD73+ B-lymphocyte below the normal range. Among CD4-lymphocytes three out of 10 patients had percentages of CD73+ below the normal range and four out of 10 patients had decreased percentages of CD73+ CD8-lymphocytes. Significant correlations were found between in vitro proliferative responses to mitogens and the number of CD73 molecules per CD73+ lymphocyte (rs = 0.60, P < 0.01) and per CD73+ CD8-lymphocyte (rs = 0.64, P < 0.02). In addition, a positive correlation was found between ability to proliferate and level of ecto-5'-NT on BMC (rs = 0.53, P < 0.05). Furthermore the ability of BMC to synthesize ecto-5'-NT was studied. During 2 days culture ecto-5'-NT activity increased markedly on BMC from both patients and healthy donors. The level of activity on BMC from all patients attained levels higher than on freshly isolated BMC from healthy donors. This shows that the decreased levels of ecto-5'-NT found on freshly isolated BMC from patients with IGD is due to defective regulation of the enzyme activity in vivo.
CD73是一种双功能糖基磷脂酰肌醇锚定的白细胞分化抗原，具有特异性胞外5'-核苷酸酶（ecto-5'-NT）活性，是一种辅助性T淋巴细胞激活分子。本研究的目的是调查一组原发性免疫球蛋白缺乏症（IGD）患者血液单核细胞（BMC）上CD73的表达情况。该组患者BMC上的ecto-5'-NT水平显著降低（P = 0.002），且每个CD73+淋巴细胞上的CD73分子数量减少（P = 0.01）。10名患者中有5名CD73+淋巴细胞百分比降低。在B淋巴细胞中，患者的CD73+细胞百分比正常，但10名患者中有4名每个CD73+ B淋巴细胞上的CD73分子数量低于正常范围。在CD4淋巴细胞中，10名患者中有3名CD73+百分比低于正常范围，10名患者中有4名CD73+ CD8淋巴细胞百分比降低。发现对有丝分裂原的体外增殖反应与每个CD73+淋巴细胞（rs = 0.60，P < 0.01）和每个CD73+ CD8淋巴细胞（rs = 0.64，P < 0.02）上的CD73分子数量之间存在显著相关性。此外，发现增殖能力与BMC上的ecto-5'-NT水平之间存在正相关（rs = 0.53，P < 0.05）。此外，还研究了BMC合成ecto-5'-NT的能力。在2天的培养过程中，患者和健康供体的BMC上的ecto-5'-NT活性均显著增加。所有患者BMC上的活性水平均高于健康供体新鲜分离的BMC上的活性水平。这表明在IGD患者新鲜分离的BMC上发现的ecto-5'-NT水平降低是由于体内酶活性调节缺陷所致。
