Publikationsserver der RWTH Aachen University
Immunglobulin A in humaner Gallenblasengalle und sein Einfluss auf die Cholesterinkristallisation
Abstract
dc:descriptionThe present dissertation looks into the influence of biliary Immunoglobulin A on the crystallization of cholesterol. Immunoglobulin A (IgA) is the most important immunoglobulin for the defense of pathogenic germs in mucous membranes. It is more resistant to chemical influences due to several modifications. Bush et. al. were able to show that a glycoprotein consisting of four sub-units inhibits the crystallization of cholesterol in the cholesterol crystallization test. This protein had been identified as immunoglobulin A together with its sub-units (heavy chain, light chain, joining chain and secretory component). Human biliary IgA was extracted from the bile of gallbladders obtained from patients undergoing cholecystectomy. It was then used in the cholesterol crystallization test which lead to a significantly lower crystallization rate. Even in comparison with colostral immunoglobulin A the difference had been significant. Therefore the inhibition of the cholesterol crystallization appears to be related to the specific immunologic features of the IgA which is partly formed within the walls of the gall bladder. For the purpose of further evaluation, the affinity of IgA to cholesterol crystals was visualized: Pure cholesterol monohydrate crystals were grown. The specific IgA affinity could be visualized by fluorescent anti-IgA-antibodies in fluorescence microscopy. Incubation with albumin minimized unspecific bindings. Optical analysis revealed an obvious enhancement of fluorescence around the cholesterol crystals. Since the cholesterol crystallization test indicated a certain difference between biliary and colostral IgA a new assay, a crystal-ELISA, had been invented in order to explore the differences in their affinity to cholesterol crystals: First the IgA concentration of several human bile probes was obtained via a validated IgA-Elisa, which was based on a known immunoglobulin-ELISA. Within the crystal-ELISA the primary antigens in the assay were immobilized cholesterol monohydrate crystals. Assessment of the cholesterol binding ability of the probe IgA in comparison to that of colostral IgA resulted in a relative crystal-binding-quotient of 1.7 to 18.6. In conclusion the affinity of biliary IgA is distinctively higher than that of colostral IgA. It can be assumed that the gall bladder mucosa produces specific antibodies due to the possibly existing contact to smallest cholesterol crystals. Genetically-related individually different imprinting of the variable part of IgA and as a consequence thereof an individually differently strong inhibition of cholesterol crystallization could explain the individually distinct risk to develop gallbladder stones.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2005
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Südfeld, Stefan
- Contributors dc:contributor
-
- Matern, Siegfried
Subjects
dc:subject × 7Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger
Identifiers
dc:identifier.*- OAI identifier oai:identifier
- oai:publications.rwth-aachen.de:62158