Evidence for absence of toxicity of T101 immunotoxin on human hematopoietic progenitor cells prior to bone marrow transplantation.
T101-ricin A-chain immunotoxin is a hybrid molecule made up of the T101 monoclonal antibody bound to the A-chain of ricin. It specifically destroys cells expressing the cell surface T65 antigen. We have designed a preclinical study to evaluate its possible use for the in vitro treatment of T-cell hematological cancers prior to autologous bone marrow transplantation. The data presented here show that conditions previously defined to produce high tumor cell killing, i.e., a 20-hr incubation at 37 degrees in the presence of T101-ricin A-chain immunotoxin up to 10(-7) M in a 10 mM ammonium chloride solution, do not affect the in vitro proliferative capacity of human hematopoietic stem cells studied by means of semisolid medium cultures (granulocyte-macrophage progenitors, burst-forming units-erythrocyte) and continuous liquid cultures (pre-granulocyte-macrophage progenitors). Therefore, autologous bone marrow transplantation with T101-ricin A-chain immunotoxin-treated graft should be feasible.
D000911:Antibodies, Monoclonal / Q000633:toxicity*; D001853:Bone Marrow / Q000187:drug effects / Q000473:pathology; D016026:Bone Marrow Transplantation; D002455:Cell Division / Q000187:drug effects; D003114:Colony-Forming Units Assay; D005615:Freezing; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D009369:Neoplasms / Q000276:immunology / Q000473:pathology; D012276:Ricin / Q000633:toxicity*
D000911:Antibodies, Monoclonal; D012276:Ricin