Figure 4

Low dose GM-CSF influences microglial responsiveness to a downstream CpG-ODN (TLR9) stimulus. Primary microglia expanded with (+) or without (-) GM-CSF were exposed to various concentrations of LPS, polyI:C or CpG-ODN for 24 h, whereupon conditioned supernatants were collected and analyzed for TNF-α (A) and MIP-2 (B) expression by ELISA (mean ± SD). Microglial cell viability was assessed using a standard MTT assay and the raw OD₅₇₀ absorbance values are reported (C). Results are representative of three independent experiments. Asterisks denote significant differences between microglia propagated in the presence and absence of GM-CSF (* p < 0.05, ** p < 0.001).