Effective immunochemotherapy of human t(4;11) leukemia in mice with severe combined immunodeficiency (SCID) using B43 (anti-CD19)-pokeweed antiviral protein immunotoxin plus cyclophosphamide

Human mixed lineage leukemia cell line RS4;11 with the t(4;11)(q21;q23) translocation causes disseminated and invariably fatal leukemia in mice with severe combined immunodeficiency. Whereas an immunotoxin constructed from the murine anti-CD18(B43) monoclonal antibody and the plant toxin pokeweed antiviral protein (B43-PAP) has a potent in vitro anti-leukemic effect against clonogenic RS4;11 cells, its activity is further potentiated by the active cyclophosphamide congener mafosfamid