Immunocytochemical study of intermediate filaments in cultured human trabecular cells

In order to study which classes of intermediate filaments (IF) comprise the IF of human trabecular cells, we undertook immunocytochemical investigations on cultured human trabecular cells using anti-keratin, anti-vimentin, anti-desmin and anti-glial fibrillar acidic protein (GFAP) rabbit sera. Immunostaining with the keratin antibody and the GFAP antibody only produced nonspecific staining. Immunostaining with the vimentin antibody and the desmin antibody produced intracytoplasmic filamentous staining. Pretreatment of the cells with colcemid to induce the perinuclear concentration of IF resulted in the demonstration of a characteristic perinuclear immunofluorescence, confirming the existence of vimentin and desmin. Some cells showed particularly strong positivity to desmin. The desmin antibody used in this study only faintly labeled the IF of cultured human skin fibroblasts, known to contain vimentin but not desmin. These results suggest that the IF of human trabecular cells are composed of vimentin and desmin, and that human trabecular cells possess muscle cell-like functions.