Pidgeon C, Schreiber R D, Schultz R M
J Immunol. 1983 Jul;131(1):311-4.
High concentrations of a murine T cell hybridoma culture supernatant containing macrophage-activating factor (MAF) rendered resident mouse peritoneal macrophages cytotoxic for P815 mastocytoma cells. The capacity of the hybridoma-derived MAF (MAFH) to induce tumoricidal activity increased 10(3) to 10(4)-fold when the lymphokine was encapsulated into liposomes. Combinations of MAFH and poly(I) X poly(C) acted synergistically to render macrophages potently cytotoxic. Subthreshold (nonactivating) concentrations of free or liposome-encapsulated MAFH increased the potency of free poly(I) X poly(C) and liposome encapsulated poly(I) X poly(C). Either as free agent or encapsulated in liposomes, single-stranded poly(I) or poly(C) did not activate macrophages in the presence or absence of MAFH. Double-stranded poly(I) X poly(C) was thus required for macrophage activation and synergism with MAFH.
含有巨噬细胞激活因子（MAF）的小鼠T细胞杂交瘤培养上清液的高浓度制剂，可使驻留的小鼠腹腔巨噬细胞对P815肥大细胞瘤细胞具有细胞毒性。当将这种淋巴因子包封于脂质体中时，杂交瘤衍生的MAF（MAFH）诱导杀肿瘤活性的能力可提高10³至10⁴倍。MAFH与聚肌苷酸×聚胞苷酸（poly(I) X poly(C)）联合作用具有协同效应，可使巨噬细胞具有强大的细胞毒性。游离的或脂质体包封的MAFH的阈下（非激活）浓度可提高游离的poly(I) X poly(C)和脂质体包封的poly(I) X poly(C)的效力。无论是作为游离剂还是包封于脂质体中，单链的聚肌苷酸或聚胞苷酸在有或没有MAFH存在的情况下均不能激活巨噬细胞。因此，巨噬细胞激活以及与MAFH协同作用需要双链的poly(I) X poly(C)。
