[21] Methods for the Attachment of Haptens and Proteins to Erythrocytes

This chapter discusses the methods for the attachment of haptens and proteins to erythrocytes. Erythrocytes to which antigens or antibodies are adsorbed or conjugated have been used extensively as target cells for the detection of antibodies and antigenic substances. The reaction of antigen-bearing erythrocytes with the complementary antibody results in agglutination or initiates a complement-dependent hemolysis. The antigen-bearing erythrocytes have been used in the quantitation of antigen by the inhibition of passive immune hemolysis. Such indicator erythrocytes have also been used to quantitate antigen-binding cells by rosette assay and antibody-forming cells by plaque-forming cell assays. Moreover, these indicator cells can be used for enumerating antigen-bearing cells by a reverse rosette assay and for counting antigen-secreting cells by a reverse plaque-forming cell assay. Assays using antigen-bearing erythrocytes to detect hybridomas secreting the desired antibody can be found elsewhere. In addition, the new coupling methods are discussed in this chapter.