INFLUENCE OF HEAVY-METAL IONS ON ANTIBODIES AND IMMUNE-COMPLEXES INVESTIGATED BY DYNAMIC LIGHT-SCATTERING AND ENZYME-LINKED-IMMUNOSORBENT-ASSAY

The effect of Cd2+, Pb2+, Hg2+ and Cu2+ on the aggregation behaviour o f monoclonal rat-IgG1-anti-mouse antibodies (kappa-light chain specifi c) and their antibody-antigen complexes with monoclonal mouse-IgG1 is reported. Investigations were done using the dynamic light scattering method. Cd2+ ions affected the hydrodynamic properties of the antibodi es and the immune complex formation very little. More than 4 Cu2+ ions per antibody molecule led to large insoluble aggregates. Pb2+ ions al so interacted with antibodies and immune complexes. Instead of 'monome ric' antibodies (Ab) or immune complexes (Ab(1)Ag(1)), large soluble a ggregates were detectable in the solution. Hg2+ ions induced complex f ormation with 3-4 antibodies per aggregate. Possible kinds of interact ion are discussed. Additionally, we tested the antigen binding activit y of metal-treated antibodies in ELISA-tests. The Sandwich ELISA techn ique was used to investigate the serological activity of the metal-tre ated antibodies, i.e., the reaction with the specific antigen. For the se experiments we used the same monoclonal antibodies, mouse-IgG1 and rat-IgG1-anti-mouse. The influence of the above mentioned heavy metal ions was investigated up to a 10-fold molar excess over the antibody c oncentration. Even at these 'unphysiological' high metal ion concentra tions an inhibition of the antibody-antigen binding activity was not d etectable.