Therapy with allogeneic immune peritoneal cells.

cell populations were freed of lymphocytes, so that the suppressive effect could be attributed specifically to macro phages. Brunner et a!. (5, 6) and Alexander et a!. (1) have shown that immune lymph node cells and lymphoid cells from the spleen can also eradicate tumor cells. This paper describes experiments in which allogeneic immune peritoneal cells are used for the eradication of cancer in the syngeneic tumor-bearing mice. This system has the advantage of being independent from the im munogenicity of the tumor, which may be very weak. Moreover, the cytotoxicity of allogeneic immune peritoneal cells is strong and reproducible (7). The question of which main cell type (macrophage or lymphocyte) is acting as effector cell in this in vivo system was also investigated. Part of these results were described in a preliminary report (8). MATERIALS AND METHODS Mice. Purebred (a) C57BL, (b) DBA/2 mice, and (c) CBA mice, 8 to 10 weeks old, were used (a) as a source of immune peritoneal cells (macrophages and lymphocytes), (b) for growth of the syngeneicascitic SL2 lymphoma and as SL2-bearing mice to be cured, and (c) as source of TLC5 lymphoma cells. Lymphomas. The DBA/2 lymphoma SL2, which arose spontaneously as an ascitic tumor, and the chemically induced CBA-derived TLC5 lymphoma were maintained by weekly i.p. passage. Both lymphomas were acquired through Dr. P. Alexander. Doubling time of the SL2 lymphoma in vitro is 12 to 16 hr. Immunization. A single i.p. injection of l0@SL2 cells was given to allogeneic C57BL mice. Peritoneal cells were harvested from immunized mice at various times after immunization (see â€oeResults†•). Control C57BL mice were immunized i.p. with l0@ to 108 DBA/2 liver cells or with l0@CBA-derived TLC5 lymphoma cells. Cell Suspensions. Peritoneal cells were obtained by washing the peritoneal cavity with 5 ml of Fischer's medium (10). The cells were centrifuged and resuspended. The following cell suspensions were used: (a) 2 x 106 immune macrophages (contaminated with lymphocytes) suspended in 1 ml; (b) immune macrophages, obtained from mice given an i.p. injection of 0.25 ml Antilymphocyte serum 9 days af ter immunization and 45 mm before collection ofthe macro phages. Macrophages were contaminated with less than 3% lymphocytes, as shown by microscopic examination and counting in a hemocytometer (9 days of immune peritoneal SUMMARY The growth-inhibitory effect in vivo of murine allogeneic immune peritoneal cells (C57BL versus SL2 lymphoma cells) on SL2 lymphoma cells injected …