Low-affinity Monoclonal Antibodies are useful Tools for Tracking Oligomerized Cell Surface Receptors

Abstract

By using several examples of cell surface receptors (MHC class II, CD47, CD147) we showed that low-affinity antibodies selectively recognize clustered subsets of the respective molecules. Monovalent binding of these antibodies is kinetically unstable because of their high dissociation rate. Therefore, their sufficiently firm binding to the cell surface can be only achieved under the conditions favouring bivalent (IgG) or multivalent (IgM) interactions. From the kinetic measurements, it is evident that low-affinity whole antibodies induce receptor multimerization under increased temperature and prolonged incubation. Distinct cell types are characterized by the presence or absence of preformed multimerized receptors, which has been confirmed by several indirect biochemical methods. In the light of the importance of receptor dimerization/multimerization for signal transmission to the cell interior, we could employ low-affinity antibodies as important tools targeting oligomerized receptors and in combination with the very sensitive techniques (such as molecular recognition force microscopy) could gain more information on the cell surface topography in the future.