Ultrastrucmturaiml munogold labelling of vimentin filaments on postembedding ultrathin sections of arachnoid villi and meningiomas

Abstract

An immunoelectron microscopic technique for the labelling of vimentin intermediate filaments on postembedding ultrathin sections is reported. Arachnoid villi obtained at autopsy and meningiomas at surgery were fixed in 1% paraformaldehyde for 30 minutes, embedded without postfixation in Epon-Araldite mixture and polymerized at 37OC for 3 weeks. Ultrathin sections were etched in 2% KOH for 3 minutes and incubated with anti-vimentin monoclonal antibodies which were subsequently labelled with goat anti-mouse IgG coupled to colloidal golds. Al1 of these labelling procedures were consistently performed within 4 hours. In both arachnoidal and meningioma cells, immunogolds preferentially decorated the intermediate filaments in proportion to the concentration. Very few gold particles were seen over the nucleus, Golgi zone, mitochondria and the extracellular connective tissue fibres. The present technique may be applied to the immunogold labelling of intermediate filaments on postembedding ultrathin sections.