Identification of allergenic epitopes on Der f I, a major allergen of Dermatophagoides farinae, using monoclonal antibodies.
The antigenic and allergenic structure of Der f I, a major allergen of the house dust mite Dermatophagoides farinae (Df) was investigated by means of a panel of 11 selected monoclonal antibodies (mAb) obtained from BALB/c mice immunized with purified Der f I. The species specificity of these mAb, tested with Der f I and Der p I--the homologous allergen from Dermatophagoides pteronyssinus--was generally restricted to Der f I since 10 out of 11 mAb reacted only with this allergen. Epitope specificity of the mAb was determined by both competitive inhibition and sandwich ELISA experiments. The results indicated the presence of at least four non-overlapping, non-repeated antigenic sites on Der f I, which were recognized by one or several mAb (sites A, B, C and D). Comparative epitope specificity studies between human IgE antibodies and mice mAb were performed, on sera and basophils of Df sensitive patients, using different inhibition assays (ELISA and histamine release experiments). The degree of inhibition varied between the patients and upon the assay design. Most of the mAb tested were found to significantly inhibit the binding of human IgE to Der f I (p less than 0.01) when compared with Der p I specific mAb as a control. The mAb reacting with site A was found to be the most potent inhibitor, presenting a mean inhibition of up to 56% in ELISA as well as in histamine release experiments. The results show that both human IgE antibodies and mAb can be directed against identical or closely related epitopes of Der f I. Therefore anti-Der f I mAb constitute immunologic probes in further allergenic epitope and peptide analysis of this major mite allergen.
Unité d'Immuno-Allergie, Institut Pasteur, Paris, France.
J
J
Le Mao
A
A
Weyer
J C
JC
Mazie
S
S
Rouyre
F
F
Marchand
A
A
Le Gall
B
B
David
D000485:Allergens / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal; D039741:Antigens, Dermatophagoides; D001491:Basophils / Q000276:immunology; D001667:Binding, Competitive; D000939:Epitopes / Q000276:immunology*; D006632:Histamine / Q000378:metabolism; D006967:Hypersensitivity / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D008925:Mites / Q000276:immunology*
D000485:Allergens; D000911:Antibodies, Monoclonal; D039741:Antigens, Dermatophagoides; D000939:Epitopes; D007073:Immunoglobulin E; D006632:Histamine