Expression of tumor necrosis factor alpha in the developing nervous system.

We present evidence that tumor necrosis factor alpha (TNF-alpha) is transiently expressed at specific times during embryogenesis in precisely defined areas of the nervous system in two different classes of vertebrates. In murine embryos, TNF-alpha was detected in the brain, neural tube and peripheral mixed spinal nerves. In the chick embryo, TNF-alpha was observed in the brain neuroepithelium and in the developing Purkinje neurons of the cerebellum. Western immunoblot analysis revealed that brain tissue from both mouse and chick embryos contained a 50 kDa protein showing immunoreactivity with anti-TNF-alpha antibody. These results suggest that TNF-alpha participates in the normal development of the vertebrate brain and spinal cord.