Purification and Characterization of Tumor Inhibitory Factor-2: Its Identity to Interleukin

Charlotte Fryling, Markar Dombalagian, Wilson Burgess, Nurit Hollander, Alain B. Schreiber, Joseph Haimovich*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The tumor inhibitory factor-2 from the conditioned medium of the human rhabdomyosarcoma cell line A673 was purified and sequenced. The 19 N-terminal amino acid residues were identical to those of human interleukin 1 (IL-1), corresponding to the residues 119–137 of the IL-lα precursor. The purified material had an apparent molecular weight similar to that of the mature secreted form of IL-lα (Mr 17,400). In addition, similarly to IL-1, it induced the production of IL-2 by T-cells. The purified protein inhibited the growth of the A673 cells from which it was derived, suggesting that it may act as an autocrine growth inhibitor. It also inhibited the growth of a human adenocarcinoma of the lung and three human mammary carcinomas, but not of two human melanoma cell lines. In contrast, it stimulated the proliferation of normal human fibroblasts. These biological activities, previously assigned to a putative tumor inhibitory factor molecule, are apparently due to the production by the tumor cells of IL-1α.

Original languageEnglish
Pages (from-to)3333-3337
Number of pages5
JournalCancer Research
Issue number12
StatePublished - 15 Jun 1989


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