This hybridoma cell line was described to secrete a mouse monoclonal antibody (IgG) that reacts with rat type 1 fibers in immunofluorescence and with rat type 1 MHCs (myosin heavy chain) in western blotting; the cell line was established in 1986 by fusion of NSO myeloma cells with spleen cells from a BALB/c mouse that had been immunized with purified myosin from bovine atrium