Crystal structure of timothy grass allergen Phl p 12.0101 reveals an unusual profilin dimer

Timothy grass pollen is a source of potent allergens. Among them, Phl p 1 and Phl p 5 are thought to be the most important, as a majority of timothy grass-allergic individuals have IgE antibodies directed against these two allergens. The profilin from timothy grass (Phl p 12) has been registered as a minor allergen, with up to 35% of individuals in populations of grass pollen allergic patients showing IgE binding to Phl p 12. Profilins are primarily minor allergens and are known for a high likelihood of co-sensitization as well as cross-reactivity situations caused by their sequence and structure similarity. The crystal structure of Phl p 12.0101 was determined and it revealed that this allergen may form an unusual dimer not previously observed among any profilins. For example, the Phl p 12 dimer has a completely different geometry and interface when compared with the latex profilin (Hev b 8) dimer that has its crystal structure determined. The structure of Phl p 12.0101 is described in the context of allergenic sensitization and allergy diagnostics. Moreover, the structure of the Phl p 12.0101 dimer is discussed, taking into account the production of recombinant allergens and their storage.

Incidence of anti-Der f 2 and anti-Zen 1-specific immunoglobulin E antibodies in atopic dogs from South-East England

Recent studies from North America and continental Europe have reported Zen 1 as a major allergen in atopic dogs, and Der f 2 as a minor allergen. In contrast, Der f 2 is considered a major allergen in Japan. In this study, allergen-specific IgE against Der f 2, Zen 1 and crude Dermatophagoides farinae (DF) was determined using ELISA assays in English atopic dogs. Serum samples were obtained from 59 dogs with non-seasonal atopic dermatitis. ELISA assays using horseradish peroxidase-labelled anti-dog IgE monoclonal antibody (Bethyl; A40-125P) and recombinant Der f 2 (Zenoaq), natural Zen 1 (Zenoaq) and DF extract (Greer Laboratories; North Carolina) were performed by Zenoaq, Fukushima, Japan. The mean optical density (OD) of each sample was determined and the cut-off value was calculated from OD readings obtained from four healthy control dogs. Der f 2, Zen 1 and DF-specific IgE antibodies were found in the serum samples taken from 57 (97 per cent), 45 (76 per cent) and 47 (80 per cent) atopic dogs, respectively, suggesting that both Zen 1 and Der f 2 are ‘major allergens’ in the South-East England.