Figure 3
Model calculations illustrating the use of cross-inhibition to demonstrate cross-reactivity and to distinguish the primary sensitising birch allergen Bet v 1 from the cross-reactive (incomplete, non-sensitizing) apple allergen Mal d 1. The type of experiment shown in figure 3A indicates what percentage of the IgE antibodies is cross-reactive (in this example: 40%, as indicated by the vertical arrow). The type of experiment shown in figure 3B shows that Bet v 1 inhibits all antibodies to Mal d 1 and provides a crude estimate of the relative affinity of the interaction of the IgE antibodies with the two allergens (if the concentration of the antibody as well as the solid-phase allergen is equal to or below the KD of the IgE-allergen interaction), as indicated by the two horizontal arrows. The parameter setting correspond to those used in figure 2, using an IgE concentration of 1, which corresponds to values for uninhibited binding of IgE of 0.2660 for IgE binding to Bet v 1 in figure 3A (KD = 1), and for IgE binding to Mal d 1 of 0.0077, 0.0341 and 0.1118 (KD = 25, 5 or 1, respectively) in figure 3B.