The effect of the removal of sialic acid, galactose and total carbohydrate on the functional activity of Campath-1H.
A monoclonal human IgG1, Campath-1H, was digested with glycosidases to assess the effect of carbohydrate on the functional activities of an IgG1. Removal of the complete carbohydrate moiety abolished complement lysis activity and antibody-dependent cell-mediated cytotoxicity, but left antigen binding activity and protein A binding activity intact. Removal of terminal sialic acid residues through glycopeptidase F digestion was not found to affect any of the tested IgG activities. Removal of the majority of the galactose residues from desialylated Campath-1H was found to reduce but not abolish complement lysis activity. Other activities were not affected by degalactosylation. This indicates a rare separation of complement lysis activity and antibody-dependent cell-mediated cytotoxicity of IgG in the way they behave under controlled conditions. This paper underlines the overall importance of carbohydrate in IgG function and stresses the relative contributions of some of the carbohydrate residues.
Boyd
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Biotechnology Analytical Laboratories, Wellcome Foundation Ltd, Kent, UK.
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Patel
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D000074323:Alemtuzumab; D000581:Amidohydrolases / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D000920:Antibody-Dependent Cell Cytotoxicity; D016466:CHO Cells; D002240:Carbohydrate Sequence; D003165:Complement System Proteins / Q000502:physiology; D006224:Cricetinae; D003601:Cytotoxicity Tests, Immunologic; D005690:Galactose / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D009101:Multiple Myeloma / Q000276:immunology; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000494:pharmacology; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D012794:Sialic Acids / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm; D007074:Immunoglobulin G; D012794:Sialic Acids; D000074323:Alemtuzumab; D003165:Complement System Proteins; D009439:Neuraminidase; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D019158:N-Acetylneuraminic Acid; D005690:Galactose