Juhlin C, Lundgren S, Johansson H, Lorentzen J, Rask L, Larsson E, Rastad J, Akerström G, Klareskog L
Department of Surgery, University of Uppsala, Sweden.
J Biol Chem. 1990 May 15;265(14):8275-9.
Two monoclonal IgG antibodies E11 and G11, which react with parathyroid and kidney tubule cells, are in the present communication demonstrated to immunostain the surface of cytotrophoblast cells in human placenta. The G11 but not the E11 antibody has earlier been found to interfere with the sensing and gating of extracellular calcium in parathyroid cells. Microfluorometric measurement of the cytoplasmic calcium (Ca2+i) concentration was performed on suspended placental cells loaded with fura-2. The E11-positive placental cells displayed biphasic and parathyroid-like increases in Ca2+i in response to extracellular Ca2+. This increase was blocked by the G11 antibody and absent in the E11-negative placental cells. A sandwich enzyme-linked immunosorbent assay was constructed in which the G11 and E11 antibodies were shown to react with the same molecule. This calcium sensor was isolated and found to consist of a single, glycosylated polypeptide of approximately 500 kDa.
两种与甲状旁腺和肾小管细胞发生反应的单克隆IgG抗体E11和G11，在本报告中被证实可对人胎盘细胞滋养层细胞表面进行免疫染色。较早前已发现，G11抗体而非E11抗体可干扰甲状旁腺细胞对细胞外钙的传感和门控。使用负载有fura-2的悬浮胎盘细胞进行细胞质钙（Ca2 + i）浓度的显微荧光测定。E11阳性的胎盘细胞对细胞外钙的反应显示出双相且类似甲状旁腺的Ca2 + i增加。这种增加被G11抗体阻断，而在E11阴性的胎盘细胞中不存在。构建了一种夹心酶联免疫吸附测定法，其中G11和E11抗体被证明可与同一分子发生反应。这种钙传感器被分离出来，发现它由一条约500 kDa的单一糖基化多肽组成。
