Shaffer M C, Foley T P, Barnes D W
J Lab Clin Med. 1984 May;103(5):783-91.
Spreading factor (SF) is a glycoprotein isolated from human plasma or serum that promotes attachment and spreading of a wide variety of mammalian cells in culture. Under appropriate conditions, this factor also affects cell proliferation and differentiation in vitro. An immunoassay employing a previously characterized monoclonal antibody to SF, with purified SF as a reference standard, was utilized to quantitate levels of SF in human plasma, serum, amniotic fluid, and urinary protein. Specific anti-SF monoclonal antibody-binding activities in individual samples of human serum were identical to specific anti-SF monoclonal antibody-binding activities in the plasma samples from which the sera were derived. Specific anti-SF monoclonal antibody-binding activity in plasma from adults, when compared with purified SF reference standards, represented an average of 4 micrograms of SF per mg plasma protein (range, 2.5 to 7 micrograms/mg). Specific anti-SF monoclonal antibody-binding activity in sera from fetal cord blood, infants, children, or adolescents was not significantly different from that of adults. Specific anti-SF monoclonal antibody-binding activities in amniotic fluid samples from pregnancies of 12 to 23 weeks' gestation were within the range observed in sera of adults. Anti-SF monoclonal antibody-binding activity in concentrated urinary protein, when compared with purified SF reference standards, represented a specific activity of 10.9 micrograms of SF per mg protein.
扩散因子（SF）是一种从人血浆或血清中分离出的糖蛋白，它能促进多种培养的哺乳动物细胞的附着和扩散。在适当条件下，该因子还会影响体外细胞的增殖和分化。采用一种先前已鉴定的抗SF单克隆抗体，并以纯化的SF作为参考标准的免疫测定法，被用于定量人血浆、血清、羊水和尿蛋白中的SF水平。人血清各个样本中的特异性抗SF单克隆抗体结合活性，与产生这些血清的血浆样本中的特异性抗SF单克隆抗体结合活性相同。与纯化的SF参考标准相比，成人血浆中的特异性抗SF单克隆抗体结合活性平均为每毫克血浆蛋白含4微克SF（范围为2.5至7微克/毫克）。胎儿脐带血、婴儿、儿童或青少年血清中的特异性抗SF单克隆抗体结合活性与成人的无显著差异。妊娠12至23周孕妇羊水样本中的特异性抗SF单克隆抗体结合活性在成人血清所观察到的范围内。与纯化的SF参考标准相比，浓缩尿蛋白中的抗SF单克隆抗体结合活性表示每毫克蛋白含10.9微克SF的比活性。
