PURIFICATION, CHARACTERIZATION AND ANTITUMOR-ACTIVITY OF A NEW CYTOKINE, HISTIOCYTE-SECRETED-FACTOR (HSF)

Purification of cytokines was carried out while monitoring their in vi vo anti-tumor activity and in vitro cytotoxic activities. As a result, purified new cytokines were obtained from culture supernatant of a hi stiocytic cell line and from rabbit serum. Briefly, a new cytokine (HS F, histiocyte-secreted-factor) was purified from the culture supernata nt of the histiocytic cell line (TYH) which we established from the pe ripheral blood of a malignant-lymphoma patient The purified samples ex hibited suppressive effects on tumor growth but no necrotizing activit y towards transplanted murine tumors. The substance displayed no cytot oxic activity against L cells (mouse fibroblast cells). The molecular weight of human HSF was about 42 kDa as estimated by SDS-PAGE. Amino-a cid sequencing of the purified HSF from the culture supernatant was pe rformed, but the N-terminal was blocked. Next, a new cytokine was puri fied from rabbit serum stimulated with Propionibacterium acnes and eli cited with lipopolysaccharide. The rabbit HSF was isolated by the same procedures as those used for the human HSF purification steps. Amino- acid sequencing was carried out after enzyme digestion. Three parts of the amino-acid sequence of the rabbit HSF were determined as LPPGLLAP MRQLRS-, NLEXFTNGMEQHYAQL-, and NPAENQAHELPNQLN-. A computer-based hom ology search demonstrated that these sequences were novel. The molecul ar weight of HSF as determined using anti-peptide antibodies revealed the following values: human HSF, 41 and 46 kDa; rabbit HSF, 35, 42 and 55 kDa. (C) 1996 Wiley-Liss Inc.