Characterisation of a humanised bispecific monoclonal antibody for cancer therapy.
A humanised bispecific monoclonal antibody (bsMAb) with binding specificity for carcinoembryonic antigen (CEA) on one arm and a radiolabelled chelate (DTPA-90Y) on the other arm was generated by consecutively transfecting the humanised genes of an anti-CEA MAb and the chimerised genes of an anti-chelate MAb into eucaryotic BHK cells using the calcium-phosphate coprecipitation technique. The antibodies secreted were of IgG3 isotype with a shortened hinge region (delta gamma 3) and light chains. Double transfectomas were screened for the secretion of bsMAbs using a double determinant enzyme-linked immunosorbent assay (ELISA) based on solid phase attached HSA-benzyl-DTPA and an anti-idiotypic MAb selective for the CEA-specific arm. After purification on two immunoaffinity chromatography columns, the humanised bsMAbs were characterised by SDS-PAGE and a quantitative binding assay in antigen excess. The purification procedure resulted in 95% reactive bispecific MAb. This humanised bsMAb may be employed in two phase radioimmunotherapy, binding to the tumour via the anti-CEA arm and localising a radiolabelled chelate with the other arm, without inducing a strong immune response observed sometimes with murine MAbs.
Bruynck
A
A
Research Laboratories of Behringwerke AG, Marburg/Lahn, Germany.
Seemann
G
G
Bosslet
K
K
D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D001667:Binding, Competitive; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology* / Q000302:isolation & purification; D004369:Pentetic Acid; D014162:Transfection
D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D007074:Immunoglobulin G; D004369:Pentetic Acid