Monoclonal antibodies to epitopes shared by actin and vimentin obtained by paramyxovirus immunization.

Three hybridoma clones producing IgM antibodies against actin were obtained from mice immunized with purified virions of paramyxoviruses. When tested on growing lung fibroblasts, ascites fluids of all clones stained in immunofluorescence cytoplasmic bundles of microfilaments, but also fibrillar networks. On colchicine-treated cells, perinuclear coils were seen in addition to microfilament bundles. In addition, one clone gave a pronounced speckled staining to the nuclei. Absorption of the ascites fluids with purified actin abolished all staining patterns. Using the Western blotting technique the antibodies reacted with both actin and vimentin polypeptides. DNase I abolished the staining of the actin filaments and of the nuclei, but left the vimentin pattern unimpaired. Thus, the monoclonal antibodies evidently reacted with epitopes common to actin and vimentin.