Responses of human birch pollen allergen-reactive T cells to chemically modified allergens (allergoids)

• Published in: Clinical and experimental allergy 1998-11, Vol.28 (11), p.1374-1383
• Main Authors: DORMANN, D, EBNER, C, JARMAN, E. R, MONTERMANN, E, KRAFT, D, RESKE-KUNZ, A. B
• Format: Article
• Language: English
• Subjects: Allergens - pharmacology; Allergic diseases; allergoid; Amino Acid Sequence; Antigens, Plant; Biological and medical sciences; birch pollen; Formaldehyde - chemistry; General aspects; Humans; Immunopathology; maleylated allergen; Medical sciences; Molecular Sequence Data; Plant Extracts - chemistry; Plant Extracts - immunology; Plant Extracts - pharmacology; Plant Proteins - chemistry; Plant Proteins - immunology; Plant Proteins - pharmacology; Pollen - adverse effects; Pollen - immunology; Respiratory Hypersensitivity - etiology; Respiratory Hypersensitivity - immunology; T-cell epitope; T-cell reactivity; T-Lymphocytes - cytology; T-Lymphocytes - drug effects; T-Lymphocytes - immunology
• ISSN: 0954-7894; 1365-2222
• DOI: 10.1046/j.1365-2222.1998.00407.x

Background Allergoids are widely used in specific immunotherapy for the treatment of IgE‐mediated allergic diseases. Objective The aim of this study was to analyse whether a modification of birch pollen allergens with formaldehyde affects the availability of T‐cell epitopes. Methods Efficient modification of the allergens was verified by determining IgE and IgG binding activity using ELISA inhibition tests. T‐cell responses to birch pollen allergoids were analysed in polyclonal systems, using peripheral blood mononuclear cells (PBMC) of five birch pollen‐allergic individuals, as well as birch pollen extract‐reactive T‐cell lines (TCL), established from the peripheral blood of 14 birch pollen‐allergic donors. To determine whether the modification of natural (n)Bet v 1 with formaldehyde or maleic anhydride results in epitope‐specific changes in T‐cell reactivities, 22 Bet v 1‐specific T‐cell clones (TCC), established from nine additional birch pollen‐allergic individuals, were tested for their reactivity with these products. Results The majority of PBMC and TCL showed a reduced response to the birch pollen extract allergoid. Bet v 1‐specific TCC could be divided into allergoid‐reactive and ‐non‐reactive TCC. No simple correlation between possible modification sites of formaldehyde in the respective T‐cell epitopes and the stimulatory potential of the allergoid was observed. Mechanisms of suppression or of anergy induction were excluded as an explanation for the non‐reactivity of representative TCC. All TCC could be stimulated by maleylated and unmodified nBet v 1 to a similar extent. Conclusion These results demonstrate differences in the availability of T‐cell epitopes between allergoids and unmodified allergens, which are most likely due to structural changes within the allergen molecule.