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Mononuclear phagocytic cells in peritoneal exudates of guinea pigs: a comparison of inducing agents
Abstract:
Peritoneal macrophages are used for immunologic assessment of the lymphokine, migration inhibitory factor (MIF). For this purpose, these cells are induced intraperitoneally in animals with inflammatory agents such as mineral oil (MO) and peptone water (PW). Purpose of the present study was two-fold: To assess the changes in biologic properties of guinea pig macrophages induced peritoneally with MO or PW as compared to control cells after administration of normal saline (NS); and to examine the suitability of induced macrophages to respond to MIF in vitro. Peritoneal exudate cells were harvested from guinea pigs 7 days following intraperitoneal injection of MO, PW or NS. They were enumerated in hemocytometers, their differential counts determined by Wright's stain and morphologic characteristics assessed by scanning electron microscopy. Functional activation of peritoneal macrophages was determined by lysosomal enzyme functions, as well as by yeast phagocytosis in vitro. Random cell migration and responses to migration inhibitory factor (MIF) were determined in Mackaness chambers. Mineral oil injection resulted in significantly higher yield of peritoneal macrophages. Greater than 70% of peritoneal exudate cells were macrophages in all three groups. Spread out structures and ruffled borders were seen in electron micrographs of MO induced cells. Such structures were less evident in PW induced cells and were absent in controls. Acid phosphatase (ACP) and beta-N-acetylglucosaminidase (B-NAG) activities as well as yeast phagocytosis significantly increased in MO and PW induced cells. Random migration and responses to MIF in Mackaness chambers remained comparable in the three experimental groups.
Insights
Mineral oil and peptone water increase peritoneal macrophage yield and activation. Induced macrophages, while morphologically altered, showed comparable migration inhibitory factor (MIF) responses to control cells.
Area of Science:
- Immunology
- Cell Biology
Background:
- Peritoneal macrophages are crucial for assessing immunologic factors like migration inhibitory factor (MIF).
- Inflammatory agents such as mineral oil (MO) and peptone water (PW) are used to induce peritoneal macrophages.
Purpose of the Study:
- To compare the biological properties of guinea pig macrophages induced by MO or PW with control cells.
- To evaluate the suitability of induced macrophages for in vitro migration inhibitory factor (MIF) assays.
Main Methods:
- Peritoneal exudate cells were harvested from guinea pigs 7 days post-injection of MO, PW, or normal saline (NS).
- Macrophage characteristics were assessed via cell counts, Wright's stain, scanning electron microscopy, lysosomal enzyme activity, phagocytosis assays, and Mackaness chambers for migration studies.
Main Results:
- Mineral oil significantly increased peritoneal macrophage yield; all groups comprised >70% macrophages.
- MO-induced macrophages exhibited enhanced spread and ruffled borders compared to PW and NS groups.
- Lysosomal enzyme activity (ACP, B-NAG) and yeast phagocytosis were significantly higher in MO and PW groups.
- Random migration and MIF responsiveness in Mackaness chambers were comparable across all three groups.
Conclusions:
- Mineral oil and peptone water effectively induce peritoneal macrophages with enhanced functional properties.
- Despite morphological and functional activation, induced macrophages maintain comparable responsiveness to migration inhibitory factor (MIF).
- Induced macrophages are suitable for in vitro immunologic assessments using MIF.