Making Weak Antigens Strong: Coupling Antigens to Red Blood Cells

Coupling antigens to red blood cells (RBCs) can increase the immunogenicity of weak antigens. Their size slows dispersal; that, and their particulate nature, also make them good targets for phagocytosis. If the source of the cells is different from the animal to be injected, they can also provide good targets for MHC class II-T-cell receptor binding. The choice of coupling method will depend on the antigen, but because of the complexity of proteins found on the surface of the RBCs, almost all chemical groups are available for coupling. Commonly used coupling methods include tannic acid, chromic chloride, and glutaraldehyde.