Monoclonal antibody to intermediate filaments of cytokeratin type. I. Drug studies and reactivity with cultured cells and tissue sections.

Establishment of a mouse-mouse hybridoma and partial characterization of IgM monoclonal antibody (M-04) identifying cytoplasmic filamentous structures is described. Immunofluorescence performed on a panel of various cultured human cell types as well as on frozen sections of normal and tumour tissues revealed specificity of M-04 antibody for cells of epithelial origin. Using MCF-7 cell line as a model, staining patterns of microtubules, microfilaments and M-04-target filaments in untreated cells were compared with those pretreated with Colcemid and Cytochalasin B. From both differential staining of various cell types and the results of drug studies it is concluded that monoclonal antibody M-04 binds to intermediate filaments of cytokeratin type. Furthermore, restricted expression of M-04 target determinant among epithelial tissues is suggested from the lack of reaction in stratified skin epithelium.