Analysis of proteins adsorbed to glass from human plasma using immunoblotting methods

Glass beads were contacted with heparinized human plasma and the adsorbed proteins eluted sequentially with 1 M tris buffer, pH 7.4, and 2% SDS. The proteins in the eluates were analyzed by SDS-polyacrylamide gel electrophoresis and immunoblotting procedures using antisera to 16 common plasma proteins. All sixteen proteins were found to be present in the eluates. The immunoblots provided evidence of contact phase activation although the role of the surface could not be ascertained since some contact activation was apparent in the starting plasma. Evidence was also obtained for the occurrence of complement activation and the fibrinogen Vroman effect on the glass bead surface. Extensive degradation of high molecular weight proteins observed previously in eluates from clinically used hemodialyzers was not observed in the present in vitro plasma experiments, thus supporting the hypothesis that such degradation is due to enzymes liberated in the in vivo experiments by blood cell damage.