Effects of paraoxon, p-nitrophenol, phenyl saligenin cyclic phosphate, and phenol on the rat interleukin 2 system

Two organophosphorus compounds, paraoxon and phenyl saligenin cyclic phosphate, as well as p-nitrophenol and phenol which are structurally related to paraoxon, were tested for their effects on interleukin 2 (IL2) production and responsiveness by rat splenocytes in vitro. Three of the four compounds inhibited mitogen-induced lymphocyte proliferation as well as IL2 production and responsiveness. However, phenyl saligenin cyclic phosphate produced maximal inhibition at a much lower concentration (0.5 microM) than p-nitrophenol (200 microM) or paraoxon (200 microM). Phenol was not inhibitory at any concentration tested (up to 250 microM). Since the production of and response to IL2 are key events in immune responses, compounds which suppress these events can be identified as potential suppressors of host resistance to disease.