High-level conjugation of chelating agents onto immunoglobulins: use of an intermediary poly( l-lysine)-diethylenetriaminepentaacetic acid carrier

• Published in: Biochimica et biophysica acta Vol. 883; no. 3; pp. 460 - 467
• Main Authors: Manabe, Yuichi, Longley, Clifford, Furmanski, Philip
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.1986
• Subjects: Antibodies, Monoclonal; Cell Line; Diethylenetriaminepentaacetic acid; Disulfides; Electrophoresis, Polyacrylamide Gel; Gadolinium; Humans; Immunoglobulin conjugate; Immunoglobulin G; Magnetic Resonance Spectroscopy; Monoclonal antibody; Pentetic Acid; Poly( l-lysine); Polylysine; Succinimides; Sulfhydryl Compounds; Immunoglobulin conjugate; DTPA; Poly( l-lysine); Diethylenetriaminepentaacetic acid; Hepes; Gadolinium; caDTPA; Monoclonal antibody; HLA; H-1; SPDP
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/0304-4165(86)90285-0

Diethylenetriaminepentaacetic acid (DTPA), a strong chelating agent, was covalently linked to murine monoclonal anti-HLA IgG 1 antibody (H-1) with the use of poly( l-lysine) ( M r 14 000) as a multivalent, intermediary carrier, via thiol-disulfide exchange reaction. The conjugates contained up to 42.5 mol DTPA per mol antibody, and retained over 90% of their antibody activity in vitro. The conjugates incorporated gadolinium (Gd) through an exchange reaction with Gd-EDTA, used to prevent colloid formation and nonspecific binding of the free metal. The IgG-poly( l-lysine)-DTPA-Gd had a greater effect per mol on proton relaxation rates than DTPA-Gd itself. Use of poly( l-lysine) as an intermediary carrier for attachment of chelating agents to IgG thus offers great potential for achieving high-specific-activity conjugates, particularly for use as biologically specific contrast agents in nuclear magnetic resonance imaging.