Monoclonal antibody to myosin derived from mice immunized with gastric mucosal cells.

A monoclonal IgMk antibody secreted by a hybrid (MUI-6) of mouse plasmacytoma NS-1 with spleen cells from a mouse immunized with canine parietal cell-enriched gastric mucosal cells was tested for immunofluorescence reactivity with gastric mucosal cells, tissue sections and monolayer cultures of rat fibroblasts. The antibody did not react with the cell membrane of parietal cells but reacted with smooth muscle fibres and skeletal muscle striations. In non-muscle cells, the antibody reacted with parietal cell cytoplasm, liver in a "polygonal" pattern, renal glomeruli, brush borders and peritubular fibrils of renal tubules, thymic medulla, brush borders of small intestinal mucosal cells, and cerebellar astrocytes, synaptic endings and synaptic glomeruli. In fibroblast monolayers, the antibody stained stress fibres in an interrupted pattern and in spreading fibroblasts, the antibody stained the microfibrillar network. Stress fibre staining was disrupted by treatment of cells with cytochalasin B. Immunoblots showed that the antibody reacted with a 200 K protein in 3T3 cells and with a preparation of myosin from rat liver.