These mice express a construct which contains the promoter and entire coding region of the murine TNF-alpha gene. A 0.77-kb EcoRI-Pst I/Sal I fragment, containing the 3'-untranslated region and polyadenylylation site of the human beta-globin gene was ligated to the 3' end of the murine gene. The transgene is expressed specifically in neuron cell bodies of the CNS and is detected in all areas tested including the cerebral cortex, cerebellum, diencephalon, brain stem, and spinal cord. Expression is not detected in astrocyte cultures, activated peritoneal macrophages or activated splenocytes. Expression is first detectable at low levels in P6 mice and increases greatly in intensity until P15 after which expression remains at high levels.