Hemagglutination and the Closest Distance of Approach of Normal, Neuraminidase‐ and Papain‐Treated Erythrocytes

Abstract

By means of potential energy versus distance diagrams, derived from electrophoretic and surface tension data, the minimum distances of approach of normal (NOR) and of neuraminidase-treated (NEU) and papain-treated (PAP) human erythrocytes could be determined. The minimum distances between the actual cell membranes of two opposing red cells are: 184 Å (NOR), 111 Å (NEU), and 113 Å (PAP), which agrees well with the fact that anti-D (Rh_o) antibodies of the IgG-class (which have a maximum distance of ≅ 120 Å between the two antibody-active sites) can hemagglutinate NEU and PAP cells, but are incapable of hemagglutinating normal D (Rh_o)-positive erythrocytes.