Production of collagen synthesis inhibitory lymphokine by human leukemic T-lymphocyte cell lines

It has been previously shown that normal human peripheral blood mononuclear cells produce a soluble factor(s) that causes selective inhibition of collagen production by cultured human diploid fibroblasts, and that stimulation of the mononuclear cells by appropriate mitogens greatly enhances its production. Because of the difficulties inherent in obtaining sufficient peripheral blood lymphocytes to purify the collagen synthesis inhibitory factor (CSIF) further and to study in detail its mechanisms of action, we have examined CSIF production by several leukemic human T- and B-lymphocyte cell lines. From the 10 lines tested (4 T- and 6 B-lymphocyte cell lines), we found 2 T-lymphocyte cell lines which produced CSIF constitutively. When the effects of various lymphocyte mitogens on CSIF production by these cell lines were examined, it was found that only phorbol myristic acid was stimulatory. Further studies demonstrated that optimal CSIF production by the phorbol myristic acid-stimulated leukemic T-lymphocytes could be achieved in a chemically defined, serum-free medium. The CSIF in the supernatants from such cultures was further purified by ammonium sulfate precipitation and gel filtration chromatography and it was shown that it had similar properties to those of CSIF produced by normal human peripheral blood lymphocytes. These findings indicate that certain leukemic T-lymphocyte cell lines are capable of CSIF production in continuous cultures. These results will permit the large scale production of CSIF and a better understanding of its mechanisms of action.