Related Experiment Video
Updated: Aug 17, 2026
A Simple and Efficient Method to Isolate Macrophages from Mixed Primary Cultures of Adult Liver Cells
Published on: May 24, 2011
An inhibitor of cell proliferation released by cultures of macrophages
Abstract:
Culture fluids from mouse peritoneal exudate cells inhibited [(3)H]thymidine incorporation by, and proliferation of, EL-4 leukemia cells, 3T3 cells, and mitogen-stimulated spleen lymphocytes. Inhibited EL-4 leukemia cells recovered their normal proliferative capacity when washed and incubated in normal medium. The inhibitory activity resided in a low-molecular-weight substance that could be absorbed by incubation with the tumor cells. This substance was dialyzable and resistant to tryptic digestion and phosphodiesterase treatment. The mononuclear phagocytes in the peritoneal exudate seemed to be the source of the inhibitor. The inhibitory material was found in the same amounts in exudates of normal mice or mice injected with peptone or infected with Listeria monocytogenes; spleen cells adherent to plastic released the inhibitor but in lesser amount. We suggest that this inhibitor may contribute to the deleterious effects found when various cells, including neoplastic ones, are cultured in the presence of macrophages.
Insights
Mouse macrophages release a low-molecular-weight substance that inhibits cell proliferation, including tumor cells. This inhibitor is dialyzable and heat-stable, suggesting a potential role in macrophage-mediated immunosuppression.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages are key immune cells involved in host defense and tissue homeostasis.
- Macrophage-derived factors can modulate the proliferation of various cell types, including lymphocytes and tumor cells.
Purpose of the Study:
- To identify and characterize an inhibitor of cell proliferation produced by mouse peritoneal exudate cells.
- To investigate the source and properties of this inhibitory substance.
Main Methods:
- Culture of mouse peritoneal exudate cells and spleen lymphocytes.
- Assay of [(3)H]thymidine incorporation and cell proliferation.
- Characterization of the inhibitory substance through dialysis, tryptic digestion, and phosphodiesterase treatment.
Main Results:
- Culture fluids from peritoneal exudate cells inhibited proliferation of EL-4 leukemia cells, 3T3 cells, and mitogen-stimulated spleen lymphocytes.
- The inhibitory activity was attributed to a low-molecular-weight, dialyzable substance resistant to tryptic digestion and phosphodiesterase.
- Mononuclear phagocytes in peritoneal exudates were identified as the primary source of the inhibitor.
Conclusions:
- A novel inhibitor of cell proliferation is produced by mouse macrophages.
- This inhibitor may contribute to the immunosuppressive effects observed in conditions involving macrophages, such as tumor growth or chronic infections.
