Expression of the human groEL stress-protein homologue in the brain and spinal cord.

A monoclonal antibody (ML30), previously shown to identify a human mitochondrial protein epitope homologous with the groEL heat-shock protein of bacteria (hsp60), was used in an immunohistochemical survey of the central nervous system in patients dying with no evidence of neurological disease and in tissue from patients dying with various neurological disorders. Staining was performed on frozen tissue sections and on formalin fixed, paraffin embedded tissue. Astrocytes in all areas showed a strong pattern of punctate granular staining, which was increased in astrocytes showing reactive changes. Oligodendrocytes stained lightly in a diffuse granular pattern as did most neurons. Ependymal cells showed apical granular positivity. Expression of the hsp60 epitope recognised by ML30 was not seen in ubiquitinated inclusion bodies in motor neuron disease, neurofibrillary tangles in Alzheimer's disease or Lewy bodies in Parkinson's disease. The epitope recognised by ML30 was stable after formalin fixation and in post mortem tissue up to 96 h after death. Expression of the human groEL stress-protein homologue in brain and spinal cord is consistent with a mitochondrial location and may provide a morphological indicator of the functional or metabolic state of cells, especially glial cells.