Thiel E, Dörmer P, Eulitz M
Histochemistry. 1975;43(1):33-49. doi: 10.1007/BF00490152.
Iodine 125, an emitter of beta-radiation with an energy lying between that of tritium and carbon-14, is investigated for its applicability in quantitative autoradiography. Absorption and geometric factors of radiation are elucidated. From this, appropriate measuring conditions are derived. The simultaneous exposure of radioactive standard sources permits the evaluation of absolute amounts of radioactivity. Standard cells with labelled membranes are a suitable source of reference taking into account the physical properties of the isotope. Sheep red blood cells are examined for their suitability as standard cells after enzymatic radioiodination. The absolute number of antigenic substances on the surface of single cells is obtained by determining the specific activity of the labelled antibody molecules, and by measuring the silver grain densities of the cells under investigation and of the standard cells. The radioactivity per standard cell can be assessed by conventional procedures. The new method is applied to the quantification of membrane-bound immunoglobulin molecules of the IgG-type on single human lymphocytes. The determination of an immunologic saturation of the labelled antibody is essential for this purpose. On the lymphocytes of a normal person and of a patient with chronic lymphatic leukaemia quite different amounts of immunoglobulins have been evaluated.
碘125是一种β辐射发射体，其能量介于氚和碳14之间，现对其在定量放射自显影中的适用性进行研究。阐明了辐射的吸收和几何因素。据此得出了合适的测量条件。放射性标准源的同时曝光可对放射性的绝对量进行评估。考虑到同位素的物理性质，带有标记膜的标准细胞是合适的参考源。对经酶促放射性碘化后的绵羊红细胞作为标准细胞的适用性进行了检测。通过测定标记抗体分子的比活性，并测量被研究细胞和标准细胞的银粒密度，可得出单细胞表面抗原物质的绝对数量。每个标准细胞的放射性可通过常规方法进行评估。该新方法应用于定量单个人类淋巴细胞上IgG型膜结合免疫球蛋白分子。为此，测定标记抗体的免疫饱和度至关重要。在正常人和慢性淋巴细胞白血病患者的淋巴细胞上，已评估出相当不同数量的免疫球蛋白。
