IMMUNOLOGICAL CROSS-REACTIVITY OF TYPE I-III INTERMEDIATE FILAMENTS IN THE COMMON CARP - IN-SITU LOCALIZATION WITH USE OF HETEROLOGOUS ANTIBODIES

The intermediate filaments (IFs) are a multigenic family of 10-nm cyto skeletal polypeptides that have been partially classified according to their cell-specific expression patterns in mammals. Since the IFs hav e been highly conserved during vertebrate evolution, the objective of the present study was to evaluate the immunological cross-reactivity a nd tissue distribution patterns of IF types I, II, and III in the comm on carp Cyprinus carpio. A panel of six heterologous antibodies were e valuated with a streptavidin-biotin-peroxidase complex detection syste m. The monoclonal antibody AE3, specific for human cytokeratins 1-8 (t ype II IFs), stained a wide variety of epithelial and nonepithelial ti ssues. Staining with the AE1 monoclonal antibody, specific for human c ytokeratins 10, 14-16, and 19 (type I IFs), resulted in similar, altho ugh generally less intense, staining of all tissues relative to the AE 3 antibody. However, the AE1 antibody stained myocardial and skeletal muscle fibers in contrast to the pattern achieved with the AE3 antibod y. The polyclonal antibody 68-121, specific for mammalian vimentin (ty pe III IFs), stained a variety of nonepithelial tissues that included various connective tissue cells (fibroblasts, muscle cells, and chondr ocytes), glial cells, neurons, lymphohematopoietic cells, and chromato phores. The 68-121 antibody also resulted in the restricted staining o f simple and stratified epithelia. In contrast, staining with the anti mammalian vimentin monoclonal antibody V9 was restricted to the cells and fibers of the retinal ganglion layer, basal lamina of the integume nt, lens epithelium, meninx, and choroid plexus epithelium. whereas th e antimammalian vimentin monoclonal antibody Vim 3B4 did not stain. St aining with the monoclonal antibody 33, specific for mammalian desmin (type III IFs), was negative except for an intense staining pattern of the ocular lens epithelium. The localization of vimentin and the cyto keratins in various epithelial and nonepithelial tissues of the common carp indicates that IF expression in teleosts is fundamentally differ ent than that in mammals relative to cell type specificity and express ion.