Binding affinities of allergens from pollen, mites, and house dust for specific IgG subclass antibodies

The distribution and affinity of IgG subclasses against various aeroallergens were assessed by inhibition of specific antibody binding. Two parameters from the dose-response curves were taken as indicative of antibody affinity: the point of 50% inhibition and the value of the slopes on double-log plots. It was found that IgG4 antibody specific for aeroallergens (i.e., from pollens of several species of Gramineae, Olea europaea, and Parietaria judaica and from house dust) usually exhibits high affinity, except for Dermatophagoides pteronyssinus. High binding affinity was also displayed by IgG1 subclass antibodies against the allergens of O. europaea and P. judaica. Distinct IgG subclass affinity profiles were observed for the allergens of grass pollen (i.e., Holcus lanatus) and dust mites (i.e., D. pteronyssinus). These results demonstrate that IgG subclass distribution, as well as antibody affinity, depends on the nature of the sensitizing allergen.