RESUMO
Cultured malignant fibrous histiocytoma (MFH) cells obtained from a spontaneous and transplantable rat tumor were studied for their ability to release tumor necrosis factor (TNF) and a factor which induces neutrophil migration in vivo. MFH cells obtained from 7-day cultures spontaneously released both activities into the supernatant (TNF: 36 ñ 9 iu tnf/ml supernatant, N = 3; neutrophil chemoattractant factor: control, Medium ip: 6 ñ 1 x 10**6; MFH supernatant: 18 ñ 1 x 106 neutrophils/cavity, H = 5). these releases were enhanced by treating MFH cells with LPS (TNF; 61 percent; neutrophil chemoattractant factor: 46 percent) and were abolished by the glucocorticoid dexamethasone (TNF: 68 percent; neutrophil chemoattractant factor: 100 percent). Anti-TNF antiserum abolished the neutrophil chemoattractant activity of the supernatants (95 percent). The release of TNF or neutrophil chemoattractant activity was reduced in cells obtained from older cultures (14 and 21 days) (TNF: 7-day culture, 36 ñ 9;14-day culture, 19ñ2;21-day culture, 19ñ 1 IU of TNF/ml; neutrophil chemoattractant activity: 7-day culture, 18 ñ 1.6; 14-day culture, 13 ñ 3;28-day culture, 8 ñ 1 x 10**6 neutrophils/cavity). The predominant cells present in 7-day cultures of MFH were histiocyte-like cells as determined by nonspecific esterase methods. The number of these cells decreased as the cultures aged (7-day culture, 71 percent; 14-day culture, 5 percent; 21-day culture, 0 percent)...