Trypanosoma brucei brucei induces interferon-gamma expression in rat dorsal root ganglia cells via a tyrosine kinase-dependent pathway

Dorsal root ganglia (DRG) were shown to express neuronal interferon (IFN)-g amma, which supports Trypanosoma brucei brucei growth,The ability of a tryp anosome-derived factor (TLTF) to activate DRG to neuronal IFN-gamma secreti on was investigated, together with the signaling pathway that might be invo lved during this process. Immunohistochemical staining revealed expression of neuronal IFN-gamma on stimulation with TLTF, which was blocked with the tyrosine protein-kinase inhibitor, tyrphostin A47, Western blot was used to analyze DRG lysates prepared at different time points after stimulation wi th TLTF. A tyrosine-phosphorylated protein induced at 15 min was seen as a band of 120-150 kDa, followed by a decrease to control levels after 30 min. A47 greatly suppressed the TLTF-induced tyrosine protein kinase activity. In addition, evidence suggesting that the transcription factor STAT-1 may p lay a key role in the TLTF signaling pathway was provided by the blocking e ffects of A47 on STAT-1 translocation to the nucleus.