Antibody 3–40 Binds to Keratin and Vimentin Intermediate Filaments

In 1983, Naito et al. reported the production of the murine monoclonal antibody 3–40, produced by immunizing mice with the human T-ALL cell line MOLT-4 (1). By cytotoxicity, absorption, and indirect immunofluorescence assays, antibody 3–40 reacted with a 35–40-Kd surface protein on most T-ALL cell lines, but not with surface molecules of normal hematopoietic cells, including thymocytes (1).