Gray L S, Masouredis S P
J Lab Clin Med. 1982 Mar;99(3):399-409.
The molar combining ratio of 125I-PrA to RBC-bound 125I-labeled IgG anti-D was 0.72 +/- 0.044. There was a significant decrease in the PrA-to-IgG combining ratio when anti-D was bound to protease-modified RBCs or to unmodified RBCs sensitized at low ionic strength, 0.49 +/- 0.034 and 0.56 +/- 0.006, respectively. These findings indicate that the interaction of RBC-bound IgG with PrA may be influenced by alterations in membrane structure, surface density, and distribution of the IgG receptor and possibly other steric factors. The quantity of RBC-bound IgG on RBCs sensitized with unlabeled serum anti-D and anti-Kell could be quantitatively assessed and correlated with antiglobulin agglutinability. Unlabeled alloantibodies were detected with the 125I-PrA at IgG densities lower than those detectable with the standard antiglobulin test. 125I-PrA, in contrast to the antiglobulin reaction, has the potential of providing increased sensitivity as well as quantitative data in assessing IgG alloantibody- or autoantibody-sensitized RBCs. (J Lab Clin Med 99:399, 1982.)
125I-蛋白A与红细胞结合的125I标记抗-D IgG的摩尔结合比为0.72±0.044。当抗-D与蛋白酶修饰的红细胞或在低离子强度下致敏的未修饰红细胞结合时，蛋白A与IgG的结合比显著降低，分别为0.49±0.034和0.56±0.006。这些发现表明，红细胞结合的IgG与蛋白A的相互作用可能受膜结构、表面密度、IgG受体分布的改变以及其他可能的空间因素的影响。用未标记的血清抗-D和抗-Kell致敏的红细胞上结合的IgG量可以进行定量评估，并与抗球蛋白凝集性相关。用125I-蛋白A检测未标记的同种抗体时，其可检测到的IgG密度低于标准抗球蛋白试验。与抗球蛋白反应相比，125I-蛋白A在评估IgG同种抗体或自身抗体致敏的红细胞时具有提高敏感性和提供定量数据的潜力。（《实验室与临床医学杂志》99:399,1982年）
