B‐cell epitopes of the allergen Chi t 1.01: peptide mapping of epitopes recognized by rabbit, murine, and human antibodies

• Published in: Allergy (Copenhagen) 2001-02, Vol.56 (2), p.118-125
• Main Authors: Van Kampen, V., Liebers, V., Sander, I., Chen, Z., Baur, X., Raulf‐Heimsoth, M., Falkenberg, F. W.
• Format: Article
• Language: English
• Subjects: allergens; Allergic diseases; Amino Acid Sequence - genetics; Animals; Antibodies - immunology; Antibodies, Monoclonal - immunology; B-Lymphocytes - immunology; Binding Sites, Antibody; Biological and medical sciences; B‐cell epitopes; Chi t 1.01 antigen; Chironomus thummi thummi; Epitopes - genetics; Epitopes - immunology; General aspects; Hemoglobins - chemistry; Hemoglobins - immunology; Humans; IgE; Immunoglobulin E - immunology; Immunopathology; Insect Proteins; Medical sciences; Mice; Mice, Inbred BALB C; Molecular Sequence Data; monoclonal antibodies; Peptide Fragments - genetics; Peptide Fragments - immunology; Peptide Mapping; rabbit antiserum; Rabbits; synthetic peptides
• ISSN: 0105-4538; 1398-9995
• DOI: 10.1034/j.1398-9995.2001.056002118.x

Background: Chi t 1.01, a hemoglobin of the midge Chironomus thummi thummi, is a widespread environmental and occupational allergen. The aim of the present investigation was to identify and compare peptides involved in B‐cell epitopes of Chi t 1.01 recognized by 15 human IgE sera, six murine monoclonal antibodies (mAbs), and a polyclonal rabbit antiserum. Methods: Synthetic peptides 19–21 amino acids long covering the whole Chi t 1.01‐sequence were covalently coupled to activated paper disks as well as adsorbed to wells of immunoplates and used for enzyme‐linked immunosorbent assay. For fine epitope mapping, we used overlapping synthetic octapeptides with one amino‐acid offset. Results: Peptides containing the amino acids 13–17, 23–29, and 40–50 were recognized by three of the mAbs, while three other mAbs reacting with none of the peptides obviously recognized conformational epitopes. Binding sites for rabbit antibodies and for human IgE antibodies were scattered over the whole molecule. The peptide 80–100 seemed to comprise at least one important IgE epitope. Depending on the method of antigen binding to the solid phase, differing results were obtained. Conclusions: Several linear epitopes in Chi t 1.01 are recognized by human IgE antibodies, by mAbs, and by polyclonal rabbit antibodies. In addition, the results indicate the presence of conformational epitopes.