Development of hemagglutination assays I. Attachment of anti-HBs antibody to stabilized erythrocytes.

Conditions favoring the coupling of antibody to human erythrocytes stabilized by a variety of reagents were studied with the use of antibody to hepatitis B surface antigen. Functional anti-HBs bound to erythrocytes was measured by radioimmune assay using 125 I-HBsAg. The attachment of anti-HBs to aldehyde-stabilized cells is favored by low pH and low ionic strength. The extent of antibody binding is both concentration and time dependent. Development of spontaneous agglutination of the coated erythrocytes occurs with the attachment of increasing quantities of anti-HBs. Although antibody was rapidly taken up by aldehyde-stabilized erythrocytes, it was initially readily dissociable, but after longer exposure became firmly bound. Experiments pertaining to the chemical nature of the more stable antibody-erythrocyte complex gave results consistent with covalent bond formation, though rigorous proof was not developed.