Cytological analysis of normal and GAN fibroblasts. (A) Fractions of wild-type and GAN cells containing vimentin aggregates in normal and low-serum media. Upon low-serum treatment, there was a dramatic increase of vimentin aggregates in GAN cells, from 12% to 43% for WG0791 cells and from 19% to 89% for WG0321 cells. Vimentin did not form aggregates in normal cells under any culture conditions. (B and C) Immunostaining of MCH070 (wild-type) cells with a polyclonal anti-vimentin antibody (B) and a monoclonal anti-pan-keratin antibody (C). A small percentage of MCH070 fibroblasts expressed both vimentin and keratins. Both of these intermediate filament proteins could form an extensive filament network. (D and E) Immunostaining of WG0321 (GAN) cells with a polyclonal anti-vimentin antibody (D) and a monoclonal anti-pan-keratin antibody (E). Similar to MCH070, a small percentage of WG0321 fibroblasts expressed vimentin and keratins. Both proteins could be found in the aggregates (white arrows). Note that some vimentin aggregates did not contain keratins (arrowheads in D). Scale bar, 10 μm.