Molecular characterization of Bip 1, a monoclonal antibody that modulates IgE binding to birch pollen allergen, Bet v 1.
Bet v 1 and homologous proteins represent major cross-reactive allergens for more than 95% of tree pollen-, fruit-, and vegetable-allergic individuals. To study the interaction of Bet v 1 and the immune system, we characterized a Bet v 1-specific mAb, Bip 1. Soluble rBip 1 Fabs were expressed in Escherichia coli and purified by affinity chromatography using immobilized Bet v 1. Bip 1 Fabs displayed a cross-reactivity to homologous allergens comparable with that of IgE Abs from allergic patients. Preincubation of Bet v 1 with Bip 1 led to an up to fivefold increase of allergic patients' IgE binding to Bet v 1. This enhancement in IgE binding may be interpreted as stabilization of a Bet v 1 state, in which certain IgE epitopes are better applicable. It also shows that allergic patients possess IgE Abs directed against different Bet v 1 conformations. The modulation of Ab binding to a given Ag by other Abs was observed also for human Bet v 1-specific IgG Abs, and may represent a novel mechanism for the regulation of specific humoral immune responses in a complex network.
Laffer
S
S
Institute of General and Experimental Pathology, Vienna General Hospital (AKH), University of Vienna, Austria.
Vangelista
L
L
Steinberger
P
P
Kraft
D
D
Pastore
A
A
Valenta
R
R
D000485:Allergens / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D052179:Antigens, Plant; D001483:Base Sequence; D003001:Cloning, Molecular; D003429:Cross Reactions; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism*; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011058:Pollen / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D017510:Protein Folding; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D012995:Solubility
D000485:Allergens; D000911:Antibodies, Monoclonal; D052179:Antigens, Plant; D018076:DNA, Complementary; D007140:Immunoglobulin Fab Fragments; D010940:Plant Proteins; D011994:Recombinant Proteins; C061312:Bet v 1 allergen, Betula; D007073:Immunoglobulin E