Immunoelectrophoresis

Immunoelectrophoresis is a combined technique that separates proteins by an electrophoretic procedure and then characterizes them by reacting them with appropriate antibodies known as immunoglobulins. This procedure is carried out on the same plate employing the following technique that is illustrated in figure 16. A layer of agar is deposited on a glass plate about 1- 2mm thick.  A small depression is made in the layer and the protein sample mixture placed in the depression (the top (first) diagram in figure 16).

Figure 16 An Example of an Immunoelecrophoresis Separation

A potential is applied across the plate and an electrophoretic separation is developed which is shown in the second diagram in figure 16. A trough is then cut in the gel layer just below the separation, which is then filled with the immunoglobin or antiserum that is depicted in the third diagram. The plate is then incubated for 24 hours in a high humidity environment. As a result, the immunoglobulins diffuse through the gel (without the gel drying out) to the separated proteins with which they may interact and form immunoprecipitin arcs. These arcs are often clearly visible but can also be stained for greater clarity (this is shown in the lowest diagram in (fifth diagram). In some cases, a confusing collection of multiple arcs are formed which makes interpretation difficult, It is often more convenient to employ just one type of antiserum that may interact with one specific protein only.