Monoclonal hybridoma screening by analysis of immunoglobulin light chains

A technique is described for the characterization of immunoglobulin light chains of hybridomas in culture. Immunoglobulins biosynthetically labelled with 14C are obtained from culture supernatants. Following complete reduction and alkylation light chains are separated from heavy chains and most other labelled contaminants by urea-formate gel electrophoresis. They are subsequently analyzed by isoelectric focusing using a simple transfer procedure. The method can be used to analyze up to 30 samples at a time and has a potential for the distinction of 750 light chains. The technique is especially useful (1) to determine the monoclonality of antibodies at an early stage in production, (2) to identify and classify antibodies having different structures but similar specificities, (3) to identify any alterations which may occur in quantity or quality of antibodies in long term culture, (4) to identify different hybridomas which produce antibodies of identical light chain subgroup.