Identification of kappa and lambda chains of the major immunoglobulin G subclasses by capillary zone electrophoresis

Immunoglobulins are present in most tissues and plasma and play crucial role in immune system. Alteration of the levels of the immunoglobulin G (IgG) subclasses (IgG1, IgG2, IgG3 and IgG4) is an indication of a disturbed immunological response. The aim of the present study was the development of a capillary electrophoresis (CE) method for the analysis of IgG subclasses in respect to their variable kappa and lambda chains. Various analytical conditions and CE modes, including capillary zone electrophoresis (CZE), capillary isoelectric focusing (CIEF) and micellar electrokinetic capillary chromatography (MECC) have been thoroughly studied. CZE was found to be the most convenient way to separate IgG subclasses. Three of the human IgG subclasses were resolved using uncoated fused-silica and 50 mM phosphate, pH = 9.3, as operating buffer at 20 kV and detection at 214 nm. IgG1kappa was completely separated from IgG2kappa and IgG3kappa, whereas IgG2kappa co-migrated with IgG4kappa, which is the minor IgG subclass. Under the same conditions IgG4lambda was completely separated from IgG1lambda, IgG2lambda and IgG3lambda, enabling the identification of the various lambda chains. The developed CE method is rapid and can be applied to the identification of the major immunoglobulin G subclasses in respect to their variable kappa and lambda chains.