Inhibition by theophylline of phagocytosis in Acanthamoeba castellanii.

Theophylline inhibited the phagocytosis of latex beads by Acanthamoeba castellanii (Neff). The cells recovered the ability to engulf beads after 1-2 hr of exposure to theophylline. Cells which have been exposed to 25 mM theophylline for a period of inhibition and recovery were not inhibited further by incubation with a fresh medium containing the same concentration of theophylline. However, the medium in which the cells recovered was as effective as a fresh medium in inhibiting phagocytosis in a fresh batch of cells, suggesting that the development of insensitivity to theophylline inhibition resides with the cells themselves. Dibutyryl cyclic AMP also inhibited bead uptake.