The anti-carcinoembryonic B2C114 monoclonal antibody was radiolabeled with
99mTc by a direct method and quality control tested
in vitro by instant thin layer chromatography, gel column scanning and ...cellulose acetate electrophoresis and assessed
in vivo for radioimmunodetection on a murine spontaneous mammary carcinoma. The optimal results of percent
99mTc bound to protein were obtained at a dithiothreitol: antibody molar ratio ranging from 800:1 to 1000:1 and at a methylene diphosphonate:stannous fluoride weight ratio of 4.3:1. Although cysteine removed up to 18% of the label during the first 4h, the stability of the tracer appeared to be excellent in human serum at 37 °C and when challenged with DTPA.
99mTc-labeled B2C114 demonstrated good and specific
in vivo tumor targeting.
The expression of cell surface antigens of the spontaneous transplantable M3-murine tumour was studied by means of the monoclonal antibody (MAb) B2C114 which recognizes the human blood group-A ...carbohydrate antigen. Following radioiodination the MAb retained their immunoreactivity and demonstrated a significantly higher in vitro binding with isolated M3-tumour cells as compared with a control antibody. B2C114 revealed 10(6) antigenic sites per cell, with a constant affinity of 5.1 x 10(9)/M. Biodistribution studies showed that B2C114 discriminated between malignant tumour and mouse normal tissues. Radioimmunodetection of Balb/c mice bearing s.c. M3-tumour showed that tumour was specifically defined without subtraction 1 day after injection of the radiolabelled antibody.
An automated biosensor system designed for measuring molecular interactions in real-time and without labelling of the reactants has been used to evaluate the association/dissociation rate and ...affinity constants of bivalent monoclonal antibodies and a monovalent bispecific monoclonal antibody. Observed differences in affinity between parental and bispecific antibody produced were related to the association rate constants, since the dissociation rate constants were in the same range. Values were also closely related to radioimmunochemical data. These results indicate that the biosensor system, besides presenting several advantages for characterizing antigen-antibody interaction, is valuable for selecting monoclonal antibodies with properties which might be useful in the development of bispecific monoclonal antibodies.
The human CD38 molecule appears to mediate several diverse activities, including signal transduction, cell adhesion and cyclic ADP-ribose synthesis. In this article, the authors consolidate the ...information available on this highly interesting, multifunctional protein.
A biosensor system aimed at real-time measuring molecular interactions among label-free reactants has been used for a comparative analysis of the binding features (i.e., association-dissociation ...rates and affinity constants) as well as epitope mapping between bivalent monoclonal antibodies and the derived monovalent bispecific monoclonal antibody. The results show that observed different affinities between parental and derived bispecific antibodies concern the association rate constant, whereas the dissociation rate constants are unaltered. The apparent affinity-constant values determined by solid-phase radioimmunoassay yielded figures almost overlapping with those obtained with the biosensor instrument. The results of the present work indicate that the biosensor system has gained a key role not only as a tool for the study of antigen-antibody interactions, but also for setting up the reference parameters for the selection of the best candidates in the generation of bispecific monoclonal antibodies.
