Roberts W K, Vasil A
J Interferon Res. 1982;2(4):519-32. doi: 10.1089/jir.1982.2.519.
Macrophages activating factor (MAF) in mouse lymphokine preparations was quantitated using a tumor cell cytotoxicity assay. MAF activity was compared with gamma interferon (IFN-gamma) activity, and the lymphokine mixture subjected to a variety of protein fractionation procedures. No significant difference in the ratio of MAF activity to IFN activity was observed following any of the fractionation steps, even after MAF had been purified to a specific activity of 1 X 10(6) u/mg protein. Gel permeation using high pressure liquid chromatography showed a coincident peak of MAF and IFN activity at approximately 55 kD. Both activities were reduced at similar rates following heating at 56 degrees C or incubation at 4 degrees C in pH 2 buffer. Finally, induction of lymphokines using different inducers (mitogens or antigens) or cell populations always resulted in similar ratios of MAF activity to IFN activity. These results support the hypothesis that MAF and IFN-gamma are identical proteins.
使用肿瘤细胞细胞毒性测定法对小鼠淋巴因子制剂中的巨噬细胞激活因子（MAF）进行定量。将MAF活性与γ干扰素（IFN-γ）活性进行比较，并对淋巴因子混合物进行各种蛋白质分级分离程序。在任何分级分离步骤之后，即使MAF已被纯化至比活性为1×10（6）u/mg蛋白质，也未观察到MAF活性与IFN活性之比有显著差异。使用高压液相色谱法进行的凝胶渗透显示，MAF和IFN活性在约55 kD处有一个重合峰。在56℃加热或在pH 2缓冲液中于4℃孵育后，两种活性以相似的速率降低。最后，使用不同的诱导剂（丝裂原或抗原）或细胞群体诱导淋巴因子总是导致MAF活性与IFN活性的相似比例。这些结果支持了MAF和IFN-γ是相同蛋白质的假设。
