Hasday J D, Shah E M, Lieberman A P
Department of Medicine, University of Maryland School of Medicine, Baltimore 21201.
J Immunol. 1990 Jul 1;145(1):371-9.
The purpose of this study was to determine whether macrophages were directly stimulated by tumor cells to release TNF-alpha. We found that several murine and human tumor cell lines and crude cell membrane vesicles prepared from these tumor cells stimulated pyran copolymer-elicited murine peritoneal macrophages (PEM) to release as much as 362 +/- 69 (mean +/- SE) units of TNF activity per 10(6) PEM in vitro. By contrast, several nontransformed cells, including Con A-stimulated splenic leukocytes and CTLL cloned T lymphocytes, failed to stimulate PEM to release TNF. Antibody and complement-mediated depletion of macrophages abrogated the release of TNF; whereas depletion of NK cells and T lymphocytes did not affect tumor-stimulated TNF release, suggesting that tumor cells directly stimulated PEM to release TNF. Tumor-stimulated TNF release was rapid, peaking in 2 to 3 h with subsequent loss of TNF activity from the medium. In the absence of tumor, PEM contained detectable levels of TNF mRNA, but did not release functionally active TNF. The addition of P815 tumor cell membrane vesicles increased both TNF mRNA levels, peaking at 1 to 2 h, and release of high levels of TNF activity. Confounding effects of endotoxin were excluded by the resistance of tumor-stimulated TNF release to neutralization by polymixin B, and by the equivalent responsiveness of PEM from endotoxin-resistant (C3H/HeJ) and endotoxin-sensitive (C3H/HeN) mice to stimulation by tumor cells. Factors which stimulated PEM to release TNF could be extracted from tumor cell membrane, with 77% of the macrophage-stimulating activity recoverable in aqueous phase. In conclusion, we have demonstrated that some tumor cell lines express specific characteristics which can be recognized by macrophages and which stimulate macrophages to release TNF.
本研究的目的是确定肿瘤细胞是否直接刺激巨噬细胞释放肿瘤坏死因子-α（TNF-α）。我们发现，几种鼠类和人类肿瘤细胞系以及从这些肿瘤细胞制备的粗制细胞膜囊泡，在体外可刺激吡喃共聚物诱导的鼠腹膜巨噬细胞（PEM），每10⁶个PEM释放高达362±69（平均值±标准误）单位的TNF活性。相比之下，几种未转化细胞，包括刀豆蛋白A刺激的脾白细胞和CTLL克隆的T淋巴细胞，未能刺激PEM释放TNF。抗体和补体介导的巨噬细胞耗竭消除了TNF的释放；而NK细胞和T淋巴细胞的耗竭并不影响肿瘤刺激的TNF释放，这表明肿瘤细胞直接刺激PEM释放TNF。肿瘤刺激的TNF释放迅速，在2至3小时达到峰值，随后培养基中的TNF活性丧失。在没有肿瘤的情况下，PEM含有可检测水平的TNF mRNA，但不释放具有功能活性的TNF。添加P815肿瘤细胞膜囊泡可增加TNF mRNA水平，在1至2小时达到峰值，并释放高水平的TNF活性。肿瘤刺激的TNF释放对多粘菌素B中和具有抗性，以及内毒素抗性（C3H/HeJ）和内毒素敏感（C3H/HeN）小鼠的PEM对肿瘤细胞刺激的等效反应性，排除了内毒素的混杂影响。刺激PEM释放TNF的因子可从肿瘤细胞膜中提取，77%的巨噬细胞刺激活性可在水相中回收。总之，我们已经证明，一些肿瘤细胞系表达了可被巨噬细胞识别并刺激巨噬细胞释放TNF的特定特征。
