Fujimoto J, Levy S, Levy R
J Exp Med. 1983 Sep 1;158(3):752-66. doi: 10.1084/jem.158.3.752.
Sensitive enzyme-linked immunosorbent assays (ELISA) for the detection of human T cell antigens in soluble form have been developed. The assays use mouse monoclonal antibodies and specific anti-Leu sera prepared in rabbits by immunizing with Leu antigens absorbed to monoclonal antibody affinity columns. With these assays, Leu-1, -2, and -3 antigen signals from extracts of as few as 5 X 10(3) cells could be detected. When culture supernatants from various cell lines were tested, Leu-2 antigen, but not Leu-1 or Leu-3, was found to be present. Leu-2 antigen was present only in supernatants from T cell lines that expressed Leu-2 on their cell surface. Leu-2 antigen accumulated progressively in the supernatant of low density culture and its presence did not depend on cell proliferation or on fetal calf serum in the culture medium. The Leu-2 antigen in the supernatant was found to have only one Leu-2a determinant, whereas Leu-2 antigen from cell extracts had at least two determinants. The Leu-2 molecule was effectively purified from supernatant with an anti-Leu-2a affinity column. The purified Leu-2 antigen from supernatant of HPB-ALL cells was a single polypeptide chain of 27,000 mol wt, whereas Leu-2 antigen present on HPB-ALL cell surface was composed of two or more identical polypeptide chains of 33,000 mol wt linked by disulfide bonds. Normal human sera and sera from leukemia patients were also examined for the presence of the Leu-2 antigen. Normal human sera contained low levels of Leu-2 antigen but sera from Leu-2-positive leukemia patients had high levels. These results indicate that Leu-2 antigen is released from human T cells under physiological conditions.
已开发出用于检测可溶性人T细胞抗原的灵敏酶联免疫吸附测定法（ELISA）。这些测定法使用小鼠单克隆抗体和通过用吸附到单克隆抗体亲和柱上的Leu抗原免疫制备的兔特异性抗Leu血清。通过这些测定法，可以检测到低至5×10³个细胞提取物中的Leu-1、-2和-3抗原信号。当检测各种细胞系的培养上清液时，发现存在Leu-2抗原，但不存在Leu-1或Leu-3抗原。Leu-2抗原仅存在于细胞表面表达Leu-2的T细胞系的上清液中。Leu-2抗原在低密度培养的上清液中逐渐积累，其存在不依赖于细胞增殖或培养基中的胎牛血清。发现上清液中的Leu-2抗原只有一个Leu-2a决定簇，而细胞提取物中的Leu-2抗原有至少两个决定簇。用抗Leu-2a亲和柱从上清液中有效地纯化了Leu-2分子。从HPB-ALL细胞上清液中纯化的Leu-2抗原是一条27,000道尔顿分子量的单多肽链，而HPB-ALL细胞表面存在的Leu-2抗原由两条或更多条33,000道尔顿分子量的相同多肽链通过二硫键连接而成。还检测了正常人血清和白血病患者血清中Leu-2抗原的存在。正常人血清中Leu-2抗原水平较低，但Leu-2阳性白血病患者的血清中含量较高。这些结果表明，Leu-2抗原在生理条件下从人T细胞中释放出来。
