Glycosylation of a VH residue of a monoclonal antibody against alpha (1----6) dextran increases its affinity for antigen.
We have observed that antidextran hybridomas with potential N-linked glycosylation sites in VH have higher affinity for polymeric dextran and for isomaltoheptaose than those lacking potential glycosylation sites. In these studies we have used gene transfection and expression techniques to verify that the carbohydrate addition sites in VH were used. The carbohydrate of the VH region was accessible for binding by the lectin Con A. By ELISA analysis it was demonstrated that the aKa of the antibody for dextran was influenced by the presence of carbohydrate in VH, with the aglycosylated antibody having an aKa 15-fold lower than its untreated counterpart. The aKa for antigen of antibodies that contain carbohydrate only in their constant region was unaffected by lack of carbohydrate. Thus, not only the amino acid sequence of the variable region but also its carbohydrate moieties can determine the magnitude of the antigen-antibody interaction.
Wallick
S C
SC
Department of Microbiology, Columbia University College of Physicians and Surgeons, New York, New York 10032.
Kabat
E A
EA
Morrison
S L
SL
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D000918:Antibody Specificity; D003001:Cloning, Molecular; D003911:Dextrans / Q000276:immunology*; D006031:Glycosylation; D007143:Immunoglobulin Heavy Chains / Q000502:physiology; D007135:Immunoglobulin Variable Region / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D013329:Structure-Activity Relationship; D014415:Tunicamycin / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D003911:Dextrans; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D014415:Tunicamycin