Abstract: Continuous cell lines of macrophages are provided by the in vitro action, on mammalian macrophages withdrawn in situ, of macrophage activating substances, which cause the removal by the macrophages of the other cells present in the cellular medium withdrawn. The macrophages thus isolated are then placed in a suitable culture medium, until the establishment of a continuous line of macrophages, then the macrophages established as a continuous line are cultured in the presence of a suitable activating substance and the supernatant liquid is collected from these cultures. This supernatant contains substances inhibiting the proliferation of the cells having a rapid rate of multiplication. This supernatant liquid is, if necessary, subjected to a purification process. The product is notably useful for inhibiting human tumor cells.

Abstract: Process for obtaining cultures of tumoral cells in vitro, of specifically human origin.The cultures of tumoral cells in vitro are prepared, particularly from human tumoral cells obtained from surgical samples of malignant tumors, by introducing, into the culture system, an anti-human lymphocyte serum described in the U. S. patent application Ser. No. 440,726, filed Feb. 8, 1974, which neutralizes the cytocidic and macrophagic activities of the lymphoblastoid and of the activated monocyte cells, present in the cellular system, with respect to the tumoral cells, thus permitting the establishment of continuous lines of tumoral cells in vitro.Utilization of the continuous lines of tumoral cells in vitro thus obtained as means of elucidating the cancer process in man and as means of ascertaining the activity of new cancerostatic and cancerolytic medicaments.