Nitric oxide - activated macrophages produce large amounts of nitric oxide (NO), which induces both cytostasis and cytotoxicity to tumor cells both in vitro and in vivo.
Lipopolysaccharide (LPS) and lipid A-associated protein - studies have demonstrated that LPS and LAP are potent macrophage activators that have been shown to stimulate tumoricidal (cytostatic) activity in vitro.