Petz L D, Fink D J, Letsky E A, Fudenberg H H, Müller-Eberhard J
J Clin Invest. 1969 Nov;47(11):2469-84. doi: 10.1172/JCI105929.
The in vivo metabolism of purified third component of complement labeled with (125)-iodine (C'3-(125)I) was studied in normal subjects and in patients with acquired hemolytic anemias. 27 such studies were performed; in addition, three studies were performed using C'3i, the biologically inactive reaction product of C'3. In normal subjects the mean fractional catabolic rate of C'3 was 2.12%/hr and the normal range (defined throughout as the mean +/- 2 SD) was from 1.56 to 2.68. The mean percentage of C'3 that was intravascular was 66.6% and the normal range was from 51 to 83. The C'3 synthesis rate averaged 1.16 mg/kg per hr with a normal range of from 0.90 to 1.42. The mean serum concentration of C'3 was 1.43 mg/ml with a normal range of from 1.00 to 1.87. The fractional catabolic rate and synthesis rate of C'3 were at the upper limit of normal or were increased above normal in patients who had warm antibody autoimmune hemolytic anemia with complement on their erythrocytes and in patients with paroxysmal nocturnal hemoglobinuria studied during periods of active hemolysis. An increased C'3 synthesis rate was also found in one patient who was hematologically normal but had an active peptic ulcer and elevated serum concentration of C'3.A normal fractional catabolic rate and C'3 synthesis rate were found in patients with autoimmune hemolytic anemia associated with alpha-methyldopa administration, atypical cold antibody autoimmune hemolytic anemia, and in paroxysmal nocturnal hemoglobinuria during an asymptomatic interval. The three studies with C'3i-(125)I revealed a very rapid removal of the labeled protein from the plasma with less than 10% remaining after 2 hr and with a corresponding increase in urinary excretion rate of the label. The fractional catabolic rate of C'3i averaged 37%/hr. The findings are consistent with the previously elucidated in vitro reaction mechanism of C'3 and strengthen the concept that serum complement participates in immune reactions in vivo.
在正常受试者和获得性溶血性贫血患者中研究了用（125）碘标记的纯化补体第三成分（C'3 - （125）I）的体内代谢情况。进行了27项此类研究；此外，还使用C'3i（C'3的无生物学活性反应产物）进行了3项研究。在正常受试者中，C'3的平均分解代谢率为2.12%/小时，正常范围（ throughout定义为平均值±2标准差）为1.56至2.68。血管内C'3的平均百分比为66.6%，正常范围为51至83。C'3合成率平均为1.16毫克/千克/小时，正常范围为0.90至1.42。C'3的平均血清浓度为1.43毫克/毫升，正常范围为1.00至1.87。在红细胞上有补体的温抗体自身免疫性溶血性贫血患者和阵发性夜间血红蛋白尿患者在活跃溶血期进行研究时，C'3的分解代谢率和合成率处于正常上限或高于正常水平。在一名血液学正常但患有活动性消化性溃疡且血清C'3浓度升高的患者中也发现C'3合成率增加。在与α - 甲基多巴给药相关的自身免疫性溶血性贫血患者、非典型冷抗体自身免疫性溶血性贫血患者以及阵发性夜间血红蛋白尿患者无症状期，发现C'3分解代谢率和合成率正常。三项用C'3i - （125）I进行的研究显示，标记蛋白从血浆中清除非常迅速，2小时后剩余不到10%，且标记物的尿排泄率相应增加。C'3i的分解代谢率平均为37%/小时。这些发现与先前阐明的C'3体外反应机制一致，并强化了血清补体参与体内免疫反应的概念。
