Evaluation of the Energy of Red Blood Cell Agglutination by Monoclonal Antibodies

Abstract

The knowledge of the energy involved in cell–cell interactions has significant implications in biological and medical sciences. Red blood cells (RBC) become mutually adhered when specific (agglutinins) or nonspecific macromolecules bind adjacent cells in an irreversible or reversible form. Flow chamber technique with digital image processing was successfully applied to determine the partial separation, by shear stress, of two RBC agglutinated face to face (doublet) by specific monoclonal antibodies (MAb) and also to evaluate the shear stress required to attain this separation. The work done in separating adhered cells is then easily calculated and serves to evaluate the antibody affinity. In this work, this technique was applied to evaluate the affinity of a monoclonal antibody specific to the blood group A antigen. The specific disaggregation energy γ (i.e., the work done by the shear stress) required to disrupt a unit of adhered membrane areas between agglutinated cells was calculated. On play back of the image analysis, measurements were taken to determine the force applied to the doublet and the relative separation between both RBC. Values of γd (from 2.70 to 4.61 × 10−9 N/cm) were found to be proportional to the density (D = 27 to 55 molecules/μm2) of MAb molecules bound on the RBC membrane.