Allergen-specific immunotherapy (AIT) could affect disease progression by inducing allergen-specific IgG that blocks allergen-IgE interactions. Epitopes identified by allergy-causing and protective antibodies were poorly understood. Researchers designed an allergome-wide peptide microarray to track linear epitope binding patterns in allergic disorders and during AIT. They studied immunological responses to grass pollen allergens. They discovered that such epitopes were routinely recognized before the start of AIT and that AIT frequently resulted in enhanced antibody production against new epitopes even after 1 year of therapy. Both people who received AIT and those who did not get AIT had highly individual linear epitope binding patterns. Despite this, antibodies to certain linear epitopes were frequently generated during AIT. For example, the 2 stiff domains discovered in grass pollen group 5 allergens were linked to a variety of discontinuous epitopes previously. Investigators showed that the flexible linker that connects these domains also comprises linear epitope areas against which antibodies were produced during AIT. In conjunction with a well-defined stereotyped/public IgE response against the same allergen, they also described certain frequently recognized linear epitopes on Phl p 2. They indicated how antibodies against these epitopes might contribute to or prevent allergy. Finally, they found epitopes that elicit cross-reactive antibodies and antibodies that only bind 1 of 2 substantially identical linear epitope variations. The results emphasized the complexities of antibody recognition of linear epitopes, both the persons tested and the allergens evaluated. The study group believed that many of the results in the study could be applied to discontinuous epitopes as well and that allergen peptide microarrays could help us better understand allergen-specific antibodies in allergic illness and during AIT.