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RNA synthesis in activated macrophages I. Poly(I) X poly(C)-induced triggering of cytolytic activity is associated
European Journal of Immunology
|December 1, 1983
Summary
Polyinosinic, polycytidylic acid [poly(I) X poly(C)] activates macrophages, increasing their tumor-killing ability but decreasing RNA synthesis. This reduced RNA synthesis may serve as a novel indicator of macrophage activation.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Murine peritoneal macrophages (pM phi) are key immune cells involved in host defense.
- Polyinosinic, polycytidylic acid [poly(I) X poly(C)] is a synthetic double-stranded RNA known to activate immune cells.
Purpose of the Study:
- To investigate the impact of poly(I) X poly(C) on macrophage activation and RNA metabolism.
- To explore the relationship between poly(I) X poly(C)-induced activation, cytolytic activity, and RNA synthesis in macrophages.
Main Methods:
- Macrophages were treated with proteose-peptone and poly(I) X poly(C).
- Cytolytic activity and glucose oxidation were measured.
- RNA synthesis was assessed by [3H]uridine incorporation.
- Intracellular uridine triphosphate (UTP) pool specific activity and [32P] orthophosphate labeling were analyzed.
Main Results:
- Poly(I) X poly(C) enhanced the cytolytic activity and glucose oxidation of macrophages.
- A significant decrease in [3H]uridine incorporation into RNA was observed in activated macrophages.
- The reduction in RNA labeling correlated with poly(I) X poly(C) dose and tumoricidal activity.
- Mechanistic studies ruled out altered cell permeability or UTP pool specific activity as causes for reduced RNA labeling.
Conclusions:
- Poly(I) X poly(C)-activated macrophages exhibit a depressed rate of RNA synthesis.
- The rate of RNA synthesis could be a potential new indicator for macrophage activation.