Demonstration of Viral Antibodies by the Counterimmunoelectrophoresis Test

Neutralization tests are one of the most commonly used methods for quantifying antibodies against rabies virus (RABV). A Counterimmunoelectrophoresis Test (CIET) is another in vitro technique for titrating RABV antibodies. It is performed on an agarose slide gel and based on the reaction between antibodies present in serial dilutions of serum with RABV antigens. Binding is shown by the presence of precipitation lines that result from the migration of unbound viral antigens towards the specific antibodies present in a hyper-immune indicator serum (IS) under constant electrical current. The technique requires the production and standardization of antigen and IS, as well as the preparation of agarose slide gels, and specific chambers for electrophoresis. CIET has the ability to determine the potency of tested sera, providing results that correlate well with other techniques.