Immunoelectrophoresis (IEP) would be the first practical method for identifying and characterising proteins in complex mixtures, combining electrophoresis and immunoprecipitation.

Throughout the years, IEP has been expanded to include a range of techniques. As a general term, it has been applied to practically any methodology that incorporates electrophoresis and the antigen-antibody precipitin reaction for proteins.

Because of the differences in technical specifications across IEP versions, the technique outlined here is only applicable to traditional IEP.

Even though some manual expertise is required, IEP is versatile, reasonably easy to customise, and cost-effective because it does not require expensive equipment.

It can also distinguish between protein identities, partial identities, and nonidentities.

If enough antibodies are available, IEP could be used to study any low-viscosity bodily fluid sample and culture fluid and tissue extract.

Classic IEP is an essential tool for clinical diagnostic testing, biochemical and pharmaceutical product purity testing, and research with these characteristics.

Grabar and Williams created the term “immunoelectrophoresis” in 1953.

Immunoelectrophoresis is the precipitation of antibodies in gelatin in the presence of a field of electricity. 

It is a method that combines immunodiffusion and electrophoresis.

Electrophoresis is used to separate a mixture of antigens into its constituent elements before testing it with double immunodiffusion.

Antigens are electrophoresed after being inserted in the wells cut off in a gel (without any antibody) 

The gel is then sliced to form a through, and the antibodies are deposited.

Antibodies diffuse to come across the antigen diffusing, and the formation of precipitation and lattice ensue, allowing the antigen’s nature to be determined.

Principles of Immunoelectrophoresis

When an electric current is sent through a gel-layered slide, the antigen mixture in the wells is separated into discrete antigen components based on size and charge.

After the electrophoresis, the reaction of antigens reacting with the specific antisera is placed through the electrophoretic migration’s parallel which leads to the diffusion. 

The antiserum in the trough progresses ahead of the compound of antigen and its components, resulting in the formation of distinct precipitin lines in 18-24 hours, each demonstrating the reaction of various proteins to their individual antibodies.

Process of Immunoelectrophoresis

• On a glass slide placed horizontally, agarose gel is produced.
• Wells are carefully brought out of the zone of the application using the sample template.
• The diluted 2:3 of the sample is a diluent protein solution (20 l antigen + 10 l diluent).
• Using a 5 l pipette, apply 5 l of the sample of control and across each matching slit (Control slit and Sample slit).
• The gel is placed in a chamber of electrophoresis along with the cathodic samples on the side, and electrophoresis is performed for 20 minutes at 100 volts.
• After electrophoresis, 20 l of the matching antiserum is applied to troughs in a wet chamber and incubated at room temperature in a horizontal posture for 18- 20 hours.
• The agarose gel is laid horizontally and dried along with the help of blotter sheets.
• The gel is immersed in a saline solution for 10 minutes before being dried and washed twice more.
• The gel is dried at temperatures less than 70°C before being stained with protein staining solution for about 3 minutes, followed by decolourisation in destaining solution baths for 5 minutes.
• The gel is dried, and the findings are analysed.

Immunoelectrophoresis Applications

• The test aids in the approximate and identification quality quantification of different proteins found in serum.
• Immunoelectrophoresis was a game-changer in the identification of protein and immunology.
• Immunoelectrophoresis is mainly utilised by patients suspected of having monoclonal or polyclonal gammopathies.
• The approach is utilised to capture both normal and aberrant proteins in human serum, such as myeloma proteins.
• Analyzes complicated protein mixtures incorporating many antigens.
• When specific suspicion of protein is being deficient (e.g., hypogammaglobulinemia) produced in extra, medical diagnostic use can be beneficial (e.g., multiple myeloma).
• This approach is useful for assessing the antibody-antigen and the antigen purity, as well as recognising a single antigen among a group of antigens.
• Immunoelectrophoresis is a more traditional approach for measuring M-protein levels in serum and urine.
• Immunoelectrophoresis aids in diagnosing and assessing therapy response in a wide range of immune-related disorders.

Conclusion:

Immunoelectrophoresis is a potent analytical technique with great resolving power because it combines electrophoresis separation of antigens with immunodiffusion against an antiserum.

The improved resolution aids in the immunological analysis of serum proteins.

Immunoelectrophoresis aids in diagnosing and evaluating therapy responses in a variety of immune-related diseases.