Enhanced expression of a protein antigen (JI‐31 antigen, 30 kilodaltons) by reactive astrocytes in lacerated spinal cord

Abstract

A mouse monoclonal antibody IMAb JI-31, isotype IgG 2b was raised against an autopsy sample of cerebral white matter from a multiple sclerosis (MS) patient. MAb JI-31 recognizes a protein (JI-31 antigen) in human brain which has a molecular weight of approximately 30,000 daltons (30 kD) as determined by immunoprecipitaion followed by SDS-gel electrophoresis (reducing conditions) and autoradiography (Singh et al.: Biosci Rep 6:73–79,1986). By immunofluorescence micoroscopy,. Mab JI-31 stains glial fibrillary acidic protein (GFAP)-positive cells, namely astrocytes from GFAP (Predy et al.:Biosci Rep 7:491–502,1987). In this paper we report we report that greatly enhanced staining for JI-31 antigen is exhibited by reactive astrocytes which arise following CNS injury. (Laceration-tape surgical lesion of the rat spinal cord served as the expermental modle.) Enhanced expression of JI-31 antigen reveals some new aspect of the astrocyte response to injury, involving transformation to the reactive state. Consequently, MAb Jl-31 may be a useful marker for studies or reactive astrocytes.