IMMUNOGLOBULINS AND ALPHA(1)-ACID GLYCOPROTEIN DO NOT CONTRIBUTE TO THE CHOLESTEROL CRYSTALLIZATION-PROMOTING EFFECT OF CONCANAVALIN A-BINDING BILIARY PROTEIN

Human bile contains cholesterol crystallization-stimulating proteins t hat can be isolated by concanavalin A-Sepharose chromatography. In the past few years an increasing number of different pronucleating protei ns have been identified in the concanavalin A-binding fraction. In thi s study we attempted to estimate the relative contribution of a number of these proteins to total concanavalin A-binding pronucleating activ ity. For this purpose, concanavalin A-binding glycoproteins were isola ted from gallbladder bile samples from 12 patients with gallstones. Th e role of IgA, IgG and IgM and alpha(1)-acid glycoprotein was investig ated by means of immunoextraction. No decrease in crystallization-prom oting activity was observed after precipitation of more than 98% of th e different immunoglobulins. In addition, removal of more than 95% of alpha(1)-acid glycoprotein from different concanavalin A-binding fract ions had no significant effect on cholesterol crystallization-promotin g activity. The influence of fibronectin was estimated by addition of physiological concentrations to a model bile system. At these concentr ations fibronectin did not promote crystallization. From these data we conclude that immunoglobulins, alpha(1)-acid glycoprotein and probabl y also fibronectin do not significantly contribute to total concanaval in A-binding activity.