Identification of new T Cell Epitopes in the mold aeroallergen Aspergillus fumigatus

Abstract

Abstract Exposure and sensitization to mold is frequently associated with severe asthma that does not respond to medication. The objective of our study is to identify a comprehensive set of T cell epitopes from the mold aeroallergen Aspergillus fumigatus (Asp), which will enable the isolation and study of T cells associated with severe asthma. To date, T cell epitopes have only been identified for three Asp allergens, all of which were originally identified based on their recognition by IgE antibodies. To derive a more comprehensive picture of T cell antigen recognition in Asp, we applied our validated 2D-gel immunoproteomics methods, and probed for IgE/IgG reactivity of Asp allergic patient plasma to proteins from two Aspergillus extracts. We also mined the literature for previously studied Asp allergens and antigens. From the proteins thus identified, we generated peptides and assessed them for HLA binding bioinformatically. This resulted in the identification of a total of 2,769 predicted HLA binding peptides. In order to identify which of these peptides can be recognized by T cells, we stimulated PBMCs of Asp-reactive donors with allergen extracts and screened for cytokine production in response to these peptides. The most reactive peptides were all from newly identified antigens, but also confirmed previously identified allergens Asp f 15 and Asp f 17 as sources of broadly reactive T cell epitopes. Thus, our work identifies a comprehensive picture of T cell antigens contained in Asp and commonly recognized T cell epitopes within them. This provides a tool for future studies of the immunopathology associated with mold allergy and asthma.