Oria R, Alvarez-Hernández X, Licéaga J, Brock J H
University Department of Bacteriology and Immunology, Western Infirmary, Glasgow, Scotland, U.K.
Biochem J. 1988 May 15;252(1):221-5. doi: 10.1042/bj2520221.
The murine macrophage-like cell line P388D1 has been used as a model to investigate whether iron acquired simultaneously from different sources (transferrin, lactoferrin, and ovotransferrin-anti-ovotransferrin immune complexes) is handled in the same way. P388D1 cells bound both lactoferrin and transferrin, but over a 6 h incubation period only the latter actually donated iron to the cells. When the cells were incubated with [55Fe]transferrin and [59Fe]ovotransferrin-anti-ovotransferrin immune complexes iron was acquired from both sources. However, there was a difference in the intracellular distribution of the two isotopes, proportionally more 55Fe entering haem compounds and less entering ferritin. When the cells were precultured in a low-iron serum-free medium almost no transferrin-iron was incorporated into ferritin, whereas the proportion of immune complex-derived iron incorporated into ferritin was unchanged. Lactoferrin enhanced the rate of cellular proliferation, as measured by [3H]thymidine incorporation, despite its inability to donate iron to the cells, suggesting a stimulatory effect independent of iron donation. In contrast immune complexes inhibited cell proliferation. These findings indicate that iron acquired from transferrin and iron acquired by scavenging mechanisms are handled differently, and suggest that more than one intracellular iron transit pool may exist.
小鼠巨噬细胞样细胞系P388D1已被用作模型，以研究从不同来源（转铁蛋白、乳铁蛋白和卵转铁蛋白-抗卵转铁蛋白免疫复合物）同时获取的铁是否以相同方式处理。P388D1细胞能结合乳铁蛋白和转铁蛋白，但在6小时的孵育期内，只有后者实际向细胞提供铁。当细胞与[55Fe]转铁蛋白和[59Fe]卵转铁蛋白-抗卵转铁蛋白免疫复合物一起孵育时，两种来源的铁都被获取。然而，两种同位素在细胞内的分布存在差异，比例上更多的55Fe进入血红素化合物，而进入铁蛋白的较少。当细胞在低铁无血清培养基中预培养时，几乎没有转铁蛋白铁掺入铁蛋白，而免疫复合物来源的铁掺入铁蛋白的比例不变。乳铁蛋白尽管不能向细胞提供铁，但通过[3H]胸苷掺入法测定，它能提高细胞增殖速率，表明存在独立于铁供应的刺激作用。相反，免疫复合物抑制细胞增殖。这些发现表明，从转铁蛋白获取的铁和通过清除机制获取的铁处理方式不同，并提示可能存在不止一个细胞内铁转运池。
