BLOCKING FACTORS (SOLUBLE MEMBRANE-RECEPTORS) FOR TUMOR-NECROSIS-FACTOR AND LYMPHOTOXIN DETECTED IN ASCITES AND RELEASED IN SHORT-TERM CULTURES OBTAINED FROM ASCITES AND SOLID TUMORS IN WOMEN WITH GYNECOLOGIC MALIGNANCY

Studies were conducted to identify and establish the cell and tissue s ource of blocking factors (BF), materials that inhibit the bioactivity of human TNF and LT in vitro. Ascites and samples of solid tumors wer e collected from women with various gynecologic malignancies. Supernat ants were collected from cultures of tumor and ascites cells after 24, 48, and 72 h. Cell-free ascites (CFA) and culture supernatants were t ested for their ability to block human recombinant TNF and LT-induced lysis of L929 cells in vitro. Levels of soluble forms of the 55- and 7 5-kDa TNF/LT receptors were measured by ELISA assay in the same sample s. CFA and culture supernatants contained TNF/LT blocking factors and high levels of one or both soluble 55- and 75-kDa TNF/LT membrane rece ptors. Levels of BF bioactivity and receptors appeared rapidly, peaked at 24 h, and declined thereafter. Soluble TNF/LT receptors may be the active BF in these samples, and tumor tissues and ascitic cells may b e a source of these receptors in the ascites fluid of these patients.