A new approach to bifunctional chelate attachment to antibodies

Conference · Sun Jan 01 04:00:00 EST 1984 · J. Nucl. Med.; (United States)

OSTI ID:6801578

Wang, T S.T.; Rosen, J M; Smith, R; Fawwaz, R A; Ferrone, S; Alderson, P O

One potential problem with the synthesis of bifunctional chelates (BC) of antibodies (Abs) is inactivation of the Ab by attachment of the chelate (C) at or near the antigen (Ag) binding site. The most common method of synthesizing BC depends on attachment of a C (e.g., DTPA) to a free amino group on the Ab molecule. However, the Ab may be inactivated if this amino group is too near the Ag binding site. We examined an alternative method, with attachment of a C, desferrioxamine-B(DF), to free carboxyl groups of Ab molecules. BC of a monoclonal Ab to a melanoma-associated Ag were prepared using DF, and labeled with In-111. DF-Ab was prepared by mixing Ab, DF, and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide at pH 4.75. BC of the same Ab also were prepared, using DTPA, by the cyclic anhydride method (DTPA-Ab). Good radiolabeling yields were achieved with both DF-Ab and DTPA-Ab. The reactivity of DF-Ab and DTPA-Ab with melanoma Ag was treated in vitro. Binding of the Ab to melanoma cells and to control (lymphoma) cells was assayed. DF-Ab and DTPA-Ab demonstrated significant cell binding (61.5 and 38.2% respectively, at appropriate dilutions) when tested with melanoma cells. Neither Ab bound significantly to control cells (6.9 and 3.3% respectively). These experiments demonstrate that BC of Abs can be successfully prepared by binding C to free carboxyl groups on Abs. The DF-Ab so produced demonstrates significant reactivity with its Ag. With some Abs, as with the above anti-melanoma Ab, this method of BC preparation may result in less loss of antigenic reactivity than occurs with conventional methods.

• Research Organization: Columbia Univ., New York, NY
• OSTI ID: 6801578
• Report Number(s): CONF-840619-
• Conference Information: Journal Name: J. Nucl. Med.; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACTIVATION ENERGY
AMINES
AMINO ACIDS
ANIMAL CELLS
ANTIBODIES
ANTIGEN-ANTIBODY REACTIONS
ANTIGENS
BETA DECAY RADIOISOTOPES
BINDING ENERGY
CARBOXYLIC ACIDS
CHELATES
CHELATING AGENTS
CHEMICAL PREPARATION
COMPLEXES
DAYS LIVING RADIOISOTOPES
DISEASES
DRUGS
DTPA
ELECTRON CAPTURE RADIOISOTOPES
ENERGY
IN VITRO
INDIUM 111
INDIUM ISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LABELLING
LYMPHOMAS
MELANOMAS
MINUTES LIVING RADIOISOTOPES
MIXING
MONOCLONAL ANTIBODIES
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PH VALUE
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
SYNTHESIS
TUMOR CELLS