Polyclonal Murine and Rabbit Antibodies for the Bile Acid Isolithocholic Acid

Abstract

Bile acids are relevant markers for clinical research. This study reports the production of antibodies for isolithocholic acid, the isomer of the extensively studied lithocholic acid. The IgG titer and affinity maturation were monitored during the immunizations of three mice and two rabbits. In both animal models, polyclonal antibodies with a high selectivity and affinity were produced. The development of a direct competitive ELISA with a test midpoint of 0.69 ± 0.05 μg/L and a measurement range from 0.09–15 μg/L is reported. Additionally, the crystal structure of isolithocholic acid is described for the first time.

Keywords:

• ELISA
• crystal structure
• competitive assay
• immunization monitoring
• 3β-hydroxy-5β-cholanic acid

ACKNOWLEDGMENTS

We thank S. Flemig for MALDI-TOF/MS measurements and F. Müller for the performance of several ELISA experiments within an internship. M. Nichczynski is acknowledged for the preparation of the lithocholic acid and isolithocholic acid crystals.