Structural aspects of cross-reactivity and its relation to antibody affinity.
In the context of IgE/allergen interactions, affinity is largely determined by the stability of the allergen-IgE complex: a low affinity is usually equated with a rapid dissociation of the complex. Regular solid-phase assays are not well suited for affinity estimates because of multivalency effects, "unstirred layer" effects and "invisible" antibodies. Elution of IgE bound to solid-phase coupled allergen might be a good measure of intrinsic affinity, provided that reassociation of antibodies is prevented by a high concentration of soluble allergen. Allergen-mediated IgE-dependent triggering of a mast cell is presumably a two-step process. During the first step, the allergen is bound to a cell-bound IgE antibody and dragged over the cell surface. The second step is the interaction between this cell-bound allergen and another IgE antibody. The hypothesis is that the affinity requirements for the first step are higher than for the second. The implication is that a mast cell can be triggered by a single high-affinity antibody in combination with one or more low-affinity antibodies.
Aalberse
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RC
CLB and the Laboratory for Experimental and Clinical Immunology, Academic Medical Center, University of Amsterdam. R-Aalberse@clb.nl
Kleine Budde
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Stapel
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van Ree
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D000485:Allergens / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D000915:Antibody Affinity / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology; D006801:Humans
D000485:Allergens