High-Affinity Antibodies to the 1,4-dihydropyridine Ca2+-Channel Blockers

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 83; no. 9; pp. 2792 - 2796
• Main Authors: Campbell, Kevin P., Sharp, Alan, Strom, Molly, Kahl, Steven D.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.05.1986; National Acad Sciences
• Subjects: Animals; Antibodies; Antibodies - immunology; Antibody Specificity; Antiserum; Biochemistry; Biological and medical sciences; Calcium Channel Blockers - immunology; Calcium Channels; Cell physiology; Charcoal; Cross reaction; Dihydropyridines; Fundamental and applied biological sciences. Psychology; Immunization; Molecular and cellular biology; Neurotransmission; Nifedipine - analogs & derivatives; Nifedipine - metabolism; Nitrendipine; Pyridines; Pyridines - immunology; Rabbits; Receptors; Receptors, Nicotinic - immunology; Structure-Activity Relationship; Tritium; Ungulates; Calcium; Antibody; Rabbit; Lagomorpha; Vertebrata; Mammalia; Investigation method; Animal; Production; Inhibitor; Membrane channel; Divalent cation; Neurotransmission
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.83.9.2792

Antibodies with high affinity and specificity for the 1,4-dihydropyridine Ca2+-channel blockers have been produced in rabbits by immunization with dihydropyridine-protein conjugates. Anti-dihydropyridine antibodies were found to specifically bind [3H]nitrendipine, [3H]nimodipine, [3H]nisoldipine, and [3H]PN 200-110 (all 1,4-dihydropyridine Ca2+-channel blockers) with high affinity, while [3H]verapamil, [3H]diltiazem, and [3H]trifluoperazine were not recognized. The average dissociation constant of the [3H]nitrendipine-antibody complex was 0.06 (± 0.02) × 10-9M for an antiserum studied in detail and ranged from 0.01 to 0.24 × 10-9M for all antisera. Inhibition of [3H]nitrendipine binding was specific for the 1,4-dihydropyridine Ca2+-channel modifiers and the concentrations required for half-maximal inhibition ranged between 0.25 and 0.90 nM. Structurally unrelated Ca2+-channel blockers, calmodulin antagonists, inactive metabolites of nitrendipine, and UV-inactivated nisoldipine did not modify [3H]nitrendipine binding to the anti-dihydropyridine antibodies. Dihydropyridines without a bulky substituent in the 4-position of the heterocycle were able to displace [3H]nitrendipine binding, but the concentrations required for half-maximal inhibition were >800 nM. In summary, anti-dihydropyridine antibodies have been shown to have high affinity and specificity for the 1,4-dihydropyridine Ca2+-channel blockers and to exhibit dihydropyridine binding properties similar to the membrane receptor for the 1,4-dihydropyridine Ca2+-channel blockers.