[Interaction of model IgG complexes with lectin from Ricinus communis in solutions studied by light scattering...

In order to demonstrate the participation of galactose-containing carbohydrate epitopes on the surface of model IgG complexes (MIC) during their interaction with high molecular weight ligands, MIC were obtained. The interaction of MIC with Ricinus communis agglutinin (RCA) was studied. The time-dependent changes in the intensity of light scattering in solutions containing MIC of different molecular masses were measured after addition of RCA. It was shown that the efficiency of MIC interaction with RCA depends on the molecular mass of the former. The binding of RCA to MIC is highly specific, it being completely abolished after addition of lactose (1-15 mM). It was found that the final lactose concentration necessary for the complete inhibition of MIC interaction with RCA to take place, depends on the molecular mass of MIC. The data obtained point to the accessibility of IgG oligosaccharide antennae within the composition of MIC for the binding to high molecular weight ligands as well as to the increased density of galactose-containing epitopes on the surface of MIC resulting from the increase in their molecular mass.