Original Articles
Copyright ©The Author(s) 2001. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 15, 2001; 7(2): 198-202
Published online Apr 15, 2001. doi: 10.3748/wjg.v7.i2.198
Cholesterol crystal binding of biliary immuno-globulin A: visualization by fluorescence light microscopy
Frank Lammert, Stefan Südfeld, Norbert Busch, Siegfried Matern
Frank Lammert, Stefan Südfeld, Norbert Busch, Siegfried Matern, Department of Medicine III, University of Technology (RWTH) Aachen, Germany
Frank Lammert, graduated from RWTH Aachen as M.D. in 1993, 1995-1997 Research Fellow at Harvard Medical School (Boston), since 1998 Staff Physician at RWTH Aachen, since 1999 Junior Research Group on Genetics of Complex Hepatobiliary Diseases.
Author contributions: All authors contributed equally to the work.
Supported by research grants from Deutsche Forschungsgemeinschaft (La 997) and Ministerium fü r Schule und Weiterbildung, Wissenschaft und Forschung des Landes Nordrhein-Westfalen.
Correspondence to: Dr. S. Matern, Department of Medicine III, RWTH Aachen, Pauwelsstraβe 30, 52057 Aachen, Germany. smatern@post.klinikum.rwth-aachen.de.
Telephone: +49-241-8088590 Fax: +49-241-8888455
Received: February 6, 2001
Revised: February 26, 2001
Accepted: March 1, 2001
Published online: April 15, 2001

AIM: To assess potential contributions of biliary IgA for crystal agglomeration into gallstones, we visualized cholesterol crystal binding of biliary IgA.

METHODS: Crystal binding biliary proteins were extracted from human gallbladder bile using lectin affinity chromatography. Biliary IgA was isolated from the bound protein fraction by immunoaffinity chromatography. Pure cholesterol monohydrate crystals were incubated with biliary IgA and fluoresceine isothiocyanate (FITC)conjugated anti IgA at 37 °C. Samples were examined under polarizing and fluorescence light microscopy with digital image processing.

RESULTS: Binding of biliary IgA to cholesterol monohydrate crystals could be visualized with FITC conjugated anti IgA antibodies. Peak fluorescence occurred at crystal edges and dislocations. Controls without biliary IgA or with biliary IgG showed no significant fluorescence.

CONCLUSION: Fluorescence light microscopy provided evidence for cholesterol crystal binding of biliary IgA. Cholesterol crystal binding proteins like IgA might be important mediators of crystal agglomeration and growth of cholesterol gallstones by modifying the evolving crystal structures in vivo.

Keywords: cholelithiasis/diagnosis, biliary tract, IgA, secretory/analysis, cholesterol/metabolism, lectins/ diagnositic use, chromatography, affinity, immunoassay