INTRACELLULAR SURVIVAL AND MULTIPLICATION OF TOXOPLASMA-GONDII IN ASTROCYTES

Primary neonatal murine astrocyte cultures were used to investigate th e role of these glial cells in host defense of the central nervous sys tem (CNS) against Toxoplasma gondii. For comparison, neonatal murine m icroglial cells were also studied. Microscopic analyses revealed that uptake of T. gondii into astrocytes was parasite-driven and was follow ed by uniform intracellular survival and multiplication of tachyzoites . Treatment of astrocytes with interferon (IFN)-gamma and lipopolysacc haride (LPS) had no apparent effect on the survival or growth of T. go ndii. Microglia, on the other hand, had both an intrinsic phagocytosis -associated antitoxoplasma activity and a nitric oxide-dependent inhib itory activity that was up-regulated by IFN-gamma and LPS. The results of this study suggest that in contrast to microglial cells, astrocyte s may provide a safe harbor within the CNS for T. gondii.