Immunoelectrophoresis

Crossed 2D immunoelectrophoresis of human serum proteins with sample application bottom left. The first dimension (horizontal below) of the electrophoresis separates without antibodies, the second against it with antibodies against human serum proteins.

The immunoelectrophoresis is a qualitative method for the detection of monoclonal antibodies in the laboratory medicine .

principle

Immunoelectrophoresis (immunoelectrophoresis) combines two methods: serum electrophoresis and immunodiffusion . The patient's serum (or the sample of antigens to be examined) and a control serum are first applied to an agarose gel , more rarely on a cellulose acetate film, and separated by electrophoresis. Then antisera , acetic acid for normal electrophoresis, IgG, IgM, IgA, Kappa and Lambda are applied between the two dividing lines . This reacts with the antibodies in the patient's serum or control serum and forms characteristic precipitation lines . Depending on the type of antiserum used, the position and shape of the lines, conclusions can be drawn about the immunoglobulin present with the light chains kappa and lambda. If only one lambda band can be seen in the example shown, either free light chains of antibodies may be present, with the rarer IgE and IgD, further evidence must be provided in order to determine which of the two immunoglobulins is involved. In biochemistry and cell biology, other variants adapted to the substances examined are in use.

Special methods

Immunodiffusion electrophoresis according to Grabar and Williams

The immunodiffusion electrophoresis according to Pierre Grabar and Curtis Williams is a combination between agarose gel electrophoresis of the proteins ( antigens ) and a diffusion of their antibodies . After agarose gel electrophoresis, the antibodies, which are introduced into punched channels, diffuse against the antigen bands and form with them precipitate arches (comparable to the precipitation lines ).

Rocket immunoelectrophoresis according to Laurell

The rocket immunoelectrophoresis according to Carl-Bertil Laurell (University of Lund) is an electrophoresis of proteins ( antigen ) in an agarose gel that contains antibodies in a certain concentration. The buffer in the gel is slightly basic so that only the antigens can migrate, since most antibodies are at their isoelectric point at a slightly basic pH value and therefore cannot move electrophoretically. At the beginning of rocket immunoelectrophoresis there is an excess of antigen which leads to the formation of soluble antigen-antibody complexes. In the course of electrophoresis, the antigens bind additional antibodies and form immunoprecipitates at the equivalence point . These resemble rocket-shaped figures, the area (height) of which is proportional to the antigen concentration. For evaluation, one only measures the height of the precipitate.

indication

The detection of monoclonal antibodies by immunoelectrophoresis is particularly important in the diagnosis of multiple myeloma or Waldenström's disease , but also in the case of other diseases with malignant degeneration of immune cells.

literature

• L. Thomas (Ed.): Laboratory and diagnosis. Indication and evaluation of laboratory results for medical diagnostics . TH-Books Verlagsgesellschaft mbH, 5th edition, Frankfurt / Main 1998, p. 1468

Individual evidence

1. ↑ Laurell Quantitative estimation of proteins by electrophoresis in agarose gel containing antibodies , Anal. Biochem. 15, 1966, 45-52. Science Citation Classics, pdf .