When a virus encounters an antibody that reacts with antigenic proteins in the viral particle, the virus and antibody clump together. When carried out under appropriate conditions, this clumping reaction will produce a visible product. Using real viruses and real antibodies to demonstrate this phenomenon is prohibitively expensive for most K-12 teachers. Less costly inorganic salts can be used to simulate the reaction. This demonstration is appropriate for life science courses that introduce the concepts of viruses, antigens and antibodies; it is also appropriate as a general demonstration of diffusion.
Dr. Les Lane of the Department of Plant Pathology at the University of Nebraska, Lincoln, provided my initial exposure to this exercise.
Thomas Namey assisted in the preparation of Figures 6 and 7.
Schadler, D. L. 2003. Antigen-Antibody Testing: A Visual Simulation or Virtual Reality.
The Plant Health Instructor. DOI: 10.1094/PHI-K-2003-0224-01