Selective killing of tumor cells in vitro by an immunotoxin composed of ricin and monoclonal antibody against Ia antigen.
A monoclonal antibody (MAb-HB55) directed against a HLA class II antigen (Ia), was purified by DE-52 chromatography. The purified MAb contained less than 5% impure protein detected by SDS-PAGE. Ricin was conjugated with the MAb via a disulfide bond to construct an immunotoxin (ricin-HB55). The concentration causing fifty percent growth inhibition (IC50) was 2 x 10(-11)M for the Raji cells. In contrast, the IC50 for Molt-4 and K562 cells was 100 times higher than that for the Raji cells. B lymphocytes separated from peripheral blood lymphocytes by nylon wool were selectively killed by the conjugate, but T lymphocytes were not apparently affected. Our results demonstrate that the immunotoxin is selectively cytotoxic to Raji cells and B-cells, and may have potential for purging malignant cells from bone marrow of patients with B-cell leukemia and lymphoma.
Wu
M
M
Shanghai Institute of Immunology, People's Republic of China.
Tang
S L
SL
Zang
R J
RJ
Yu
H
H
D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000627:therapeutic use*; D000920:Antibody-Dependent Cell Cytotoxicity; D001402:B-Lymphocytes / Q000187:drug effects; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D000922:Immunotoxins / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D012276:Ricin / Q000494:pharmacology* / Q000627:therapeutic use; D013601:T-Lymphocytes / Q000187:drug effects; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D000922:Immunotoxins; D000643:Ammonium Chloride; D012276:Ricin