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Antitumor activity of macrophages grown in tumorous ascitic fluid
Abstract:
Peritoneal macrophages from mice injected with glycogen proliferated in vitro in the presence of cell-free tumorous ascites. DNA synthesis of macrophages was also induced by ascitic fluid, but did not occur in the absence of the fluid. However, macrophage growth was inhibited at a higher concentration of ascitic fluid (greater than 20%). The growth stimulating activity of this fluid was stable on heat treatment. The adherent cultured cells that proliferated were typical macrophages, as indicated by nonspecific esterase staining, pinocytosis and phagocytosis. These macrophages showed cytolytic activity against a murine tumor in the presence of wheat germ agglutinin. However, their cytotoxicity with antitumor antibody decreased during the culture period. These results indicate that tumorous ascitic fluid contains a macrophage growth factor(s) and that macrophages cultured with, and induced to proliferate by, ascitic fluid can kill tumor cells in cooperation with lectin but not antibody.
Insights
Tumorous ascites fluid contains macrophage growth factors that stimulate proliferation and DNA synthesis in macrophages. These cultured macrophages exhibit tumor-killing activity with lectins but not antitumor antibodies.
Area of Science:
- Immunology
- Cell Biology
- Cancer Research
Background:
- Peritoneal macrophages play a crucial role in immune responses.
- Tumorous ascites fluid is a complex biological medium associated with cancer progression.
- Understanding macrophage behavior in the tumor microenvironment is vital for cancer therapy.
Purpose of the Study:
- To investigate the effect of tumorous ascites fluid on macrophage proliferation and function.
- To determine if tumorous ascites fluid contains macrophage growth-promoting factors.
- To assess the cytotoxic potential of macrophages cultured in tumorous ascites fluid.
Main Methods:
- Peritoneal macrophages were isolated from mice.
- Macrophages were cultured in vitro with varying concentrations of cell-free tumorous ascites fluid.
- DNA synthesis was measured, and cell proliferation was assessed via esterase staining, pinocytosis, and phagocytosis assays.
- Cytolytic activity against a murine tumor was evaluated using wheat germ agglutinin and antitumor antibody.
Main Results:
- Tumorous ascites fluid significantly induced macrophage proliferation and DNA synthesis in a dose-dependent manner, with inhibition observed above 20% concentration.
- The growth-stimulating activity was heat-stable.
- Cultured macrophages exhibited specific cytolytic activity against a murine tumor when combined with wheat germ agglutinin, but this activity diminished over time when using antitumor antibodies.
Conclusions:
- Tumorous ascites fluid contains heat-stable macrophage growth factor(s).
- Macrophages cultured with tumorous ascites fluid can be induced to proliferate and acquire tumoricidal properties.
- The lectin-mediated cytotoxicity of these macrophages is effective, whereas antibody-mediated cytotoxicity decreases with culture duration.