Specific antibody-dependent binding of complement component C1q to hapten-sensitized lipid vesicles.

Abstract

The binding of a component of human complement (Clq) to membrane-bound specific anti-nitroxide antibodies was studied as a function of the physical properties (fluid vs. solid) of vesicle lipids. The antibodies were bound to spin-label lipid haptens in the vesicle membrane. The binding of Clq to the sensitized vesicles shows a maximum as a function of specific Ig[immunoglobulin]G concentration. The binding of antibodies and of Clq to the vesicle membrane does not depend strongly on the physical state of the membrane lipids, even at low hapten (0.05 mol %) concentrations. These results are of significance for the understanding of the effect of lipid physical states on complement depletion.