Biological significance of carbohydrate chains on monoclonal antibodies.
We have prepared monoclonal hapten-specific mouse IgG2b antibodies depleted of asparagine-linked carbohydrate chains by treating the hybridoma cells with tunicamycin. The carbohydrate-deficient antibodies behaved in an identical manner to the normal antibodies with regard to fine antigen-binding reactivity (a Fab fragment feature) and protein A binding capacity [a feature requiring integrity at the CH2 and CH3 domain-interaction regions in the constant region of the heavy chain (CH)]. However, they lost the ability to activate complement, to bind to Fc receptors on macrophages, and to induce antibody-dependent cellular cytotoxicity. Furthermore, antigen-antibody complexes produced from such carbohydrate-deficient antibodies failed to be eliminated rapidly from the circulation. We conclude that removal of carbohydrate chains from IgG molecules may have a profound and highly select impact on the biological activity to these antibodies.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000920:Antibody-Dependent Cell Cytotoxicity; D000936:Antigen-Antibody Complex; D001666:Binding Sites, Antibody; D003167:Complement Activation; D006023:Glycoproteins / Q000276:immunology; D007700:Kinetics; D051379:Mice; D011961:Receptors, Fc / Q000276:immunology; D013205:Staphylococcal Protein A / Q000276:immunology; D013329:Structure-Activity Relationship; D014415:Tunicamycin / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D006023:Glycoproteins; D011961:Receptors, Fc; D013205:Staphylococcal Protein A; D014415:Tunicamycin