Humoral and cellular cross-reactivity between Amb a 1, the major ragweed pollen allergen, and its mugwort homolog Art v 6.
Ragweed and mugwort are closely related weeds that represent the major cause of pollen allergy in late summer. Concomitant sensitization and clinical cross-reactivity frequently occur in subjects who are coexposed to both pollen species, and have implications for diagnosis and specific immunotherapy. Molecules involved in this cross-reactivity might be Amb a 1, the major ragweed pollen allergen, and Art v 6, a highly homologous allergen from mugwort. Therefore, we investigated the IgE and T cell response to Art v 6 of 60 weed pollen-allergic patients and assessed its immunological cross-reactivity with Amb a 1. Results of ELISA inhibition experiments suggested that both allergens are largely cross-reactive, but Amb a 1 possesses more IgE epitopes than Art v 6. In patients with IgE to both allergens, Amb a 1-induced T cell lines and clones responded weakly to Art v 6. Moreover, Art v 6-induced T cell lines responded stronger to Amb a 1. T cell epitope mapping of Art v 6 revealed that it contains only a few cross-reactive epitopes, which is opposed to the multiple T cell-activating regions present in Amb a 1. In summary, Amb a 1 can elicit more diverse allergen-specific IgE and T cell responses than Art v 6 and dominates the cross-reactivity with its homolog. Nevertheless, Art v 6 can act as a primary sensitizing allergen in areas with high mugwort pollen exposure, and consequently may facilitate sensitization to Amb a 1 by epitope cross-recognition of T and B cells.
Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria. beatrice.jahn-schmid@meduniwien.ac.at
Beatrice
B
Jahn-Schmid
Michael
M
Hauser
Nicole
N
Wopfner
Peter
P
Briza
Uwe E
UE
Berger
Riccardo
R
Asero
Christof
C
Ebner
Fatima
F
Ferreira
Barbara
B
Bohle
D000485:Allergens / Q000276:immunology*; D031164:Ambrosia / Q000276:immunology*; D052179:Antigens, Plant / Q000276:immunology; D019306:Artemisia / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D003429:Cross Reactions / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D010940:Plant Proteins / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; C026967:Amb a I protein, Ambrosia artemisiifolia; D052179:Antigens, Plant; C102724:Art v 1 protein, mugwort; D000939:Epitopes; D010940:Plant Proteins; D007073:Immunoglobulin E