CXCL10, but not TNF-α, synergized HIV-1-induced neuronal toxicity. (A) LDH activity was estimated in supernatants from HFN treated with HIV-1 alone or in combination with TNF-α. H2O2 was used as a positive control. (B) Mixed neuronal cultures (HFN) were co-treated with HIV-1 (250 ng/ml p24 concentration) and CXCL10 for 24 h. LDH release was estimated on cell supernatants. (C) HIV-1 and CXCL10 co-treated HFN were immunostained for GFAP (red), then counterstained with FJC (green), which stains dead neurons. Nuclear staining was done with DAPI (blue). LDH, lactate dehyrdrogenase; HFN, human fetal neurons; GFAP, glial fibrillary acidic protein; FJC, fluoro-jade C; DAPI, 4',6-diamidino-2-phenylindole.