MICROGLIAL PHAGOCYTOSIS IS MODULATED BY PROINFLAMMATORY AND ANTIINFLAMMATORY CYTOKINES

ACTIVATION of microglial cells in neurological diseases involves proli feration and the induction of phagocytic and cytotoxic properties. We studied the effects of four different cytokines on microglial phagocyt osis of latex beads to gain further insights into the signals modulati ng different aspects of microglial activity. Granulocyte/macrophage co lony stimulating factor and tumor necrosis factor-alpha enhanced micro glial phagocytic activity as measured by flow cytometry. A phagocytosi s inhibiting effect was observed after preincubation with transforming growth factor-beta 1 and interleukin-4. In conclusion, the activating and deactivating cytokines differentially regulate microglial phagocy tic activity in vitro and might also play an important role in vivo in modulating microglial activation to keep the balance between the prot ective, defensive and destructive, chronic inflammatory properties of microglia.