Affinity determinations of purified IgE and IgG antibodies against the major pollen allergens Phl p 5a and Bet v 1a: discrepancy between IgE and IgG binding strength.
Allergen-specific IgE and IgG antibodies coexist in allergic individuals, but only IgE has anaphylactogenic capacity. This study aimed to determine the association, dissociation and equilibrium constants for the interaction of allergen-specific IgE and IgG with the major grass and birch pollen allergens Phl p 5a and Bet v 1a. We isolated specific IgE and IgG antibodies from pollen allergic patients' sera by a two-step affinity chromatography protocol and controlled the high purity in a recombinant allergen chip microarray. Surface plasmon resonance measurements of polyclonal IgE and IgG species revealed that their affinities diverge widely, being in the range of 10(-10) and 10(-11) M for IgE, but only 10(-6)-10(-7) M for IgG. Moreover, murine monoclonal IgG1 antibodies against the allergens showed affinities of 10(-7)-10(-8) M. Thus, we conclude from our data that even stringently affinity matured IgG cannot score the superior affinity of IgE antibodies to allergens.
Hantusch
Brigitte
B
Department of Pathophysiology, Medical University of Vienna, Neubau AKH EB3Q, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
Schöll
Isabella
I
Harwanegg
Christian
C
Krieger
Sigurd
S
Becker
Wolf-Meinhard
WM
Spitzauer
Susanne
S
Boltz-Nitulescu
George
G
Jensen-Jarolim
Erika
E
D000818:Animals; D000915:Antibody Affinity / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology* / Q000302:isolation & purification; D007700:Kinetics; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D010940:Plant Proteins / Q000276:immunology*
D007074:Immunoglobulin G; C076049:Phl p V protein, Phleum pratense; D010940:Plant Proteins; D007073:Immunoglobulin E