Complex network of cytokines activating murine microglial cell activity against Acanthamoeba castellani.

In the central nervous system, cytokine-primed microglia play a pivotal role in host defence against Acanthamoeba castellani infections. In this study, the effect of rIL-1beta, rIL-6 or rTNF-alpha, combined or not with rIFN-gamma, on A. castellani infection of murine microglia was examined. Priming of microglial cells with either rIL-1beta or rIL-6, in the presence or absence of rIFN-gamma, triggered amebastatic activity, while the treatment of microglia with rTNF-alpha plus rIFN-gamma additively triggered, in a dose-dependent fashion, amebicidal activity. Inasmuch as NGMA affected cytokine-triggered anti-parasitic activity during the priming process, the NO-dependent pathway itself appears not to be directly involved in the anti-amebic capacities. These data suggest that the proinflammatory cytokines IL-1beta, IL-6 or TNF-alpha could trigger anti-microbial activity against A. castellani infection in the brain.