A monoclonal antibody against vimentin: characterization.

A monoclonal antibody was developed using rat cerebral cortex astrocytes purified in vitro as the antigenic material. Screening was done by labeling antibodies bound to cerebellum slices with fluorescent tagged secondary antibodies. The monoclonal antibody (RBA1) bound to intracellular filaments in all cells examined in culture. The coloration of tissue sections by RBA1 was identical to that described for polyclonal antibodies against the intermediate filament protein vimentin. In the brain this included binding to meninges, blood vessels, ependymal cells, choroid plexus lining cells and a subpopulation of astrocytes. The latter included Bergman glial fibers, white matter astrocytes and tanycytes. Müller cells in the retina and fibroblast-like cells in the skin, tongue and intestine were RBA1-positive. In immunoblots in which purified vimentin and desmin were run on SDS and transferred to nitrocellulose paper, RBA1 bound to vimentin but not desmin. When cultured astrocyte proteins were blotted, the antibody bound to both GFAP and vimentin, but no GFAP staining was observed in any of the tissue section staining. Purified vimentin blocked tissue and cultured cell binding of the antibody. Therefore RBA1 is considered to be an antibody specific for the intermediate filament protein vimentin.