ONLINE POST-CAPILLARY AFFINITY DETECTION OF IMMUNOGLOBULIN-G SUBCLASSES AND MONOCLONAL-ANTIBODY VARIANTS FOR CAPILLARY ELECTROPHORESIS

Human immunoglobulin G (IgG) subclasses each play a unique role in an immune response to foreign antigens. Three of the human IgG subclasses have distinct electrophoretic mobilities and are resolved by capillar y zone electrophoresis (CZE). A post-capillary reactor is constructed to allow on-line addition of fragment B (of protein A)-fluorescein to form affinity complexes with separated IgG subclasses. Post-capillary affinity detection provides selective identification of human IgG subc lasses and illustrates the effect of affinity binding constant on dete ction sensitivity. Additionally, post-capillary affinity detection for CZE facilitates rapid and selective heterogeneity analysis of mouse m onoclonal anti-(human-alpha(1)-antitrypsin) and anti-human follicle st imulating hormone in complex sample matrices. A constant mobility diff erence is observed between the antibody isoforms, likely the result of charge heterogeneity due to deamination, degradation or variation in sialic acid content. (C) 1997 Elsevier Science B.V.