Influence of the 3D-conformation, glycan component and microheterogeneity on the epitope structure of Ole e 1, the major olive allergen. Use of recombinant isoforms and specific monoclonal antibodies as immunological tools.
Ole e 1 is the main allergen of olive pollen, which is a major cause of pollinosis in countries of the Mediterranean area. Nine Ole e 1-specific murine monoclonal antibodies (mAbs), as well as two Ole e 1-isoforms and two Ole e 1-like allergens from lilac and privet, all of them obtained in Pichia pastoris by recombinant methods, have been used as tools to determine the role of the three-dimensional (3D)-folding, the glycan component and several point changes of the amino acid sequence in the binding of murine IgG mAbs and human IgE to the olive allergen. Seven mAb families (F1-F7) were established, two of which (F1 and F2) recognize continuous epitopes. The carbohydrate moiety of Ole e 1 was involved in the binding to F2 and F4, whereas F3 and F7 were able to bind to all Ole e 1 variants. The remaining families of IgG murine antibodies exhibited different affinities for the antigens assayed in a native or denatured conformation. Although the binding of human IgE to Ole e 1 was not affected by heat treatment, it was shown to be strongly dependent on the integrity of the disulfide bridges and was partially inhibited by F3-F7 IgG antibodies, their individual values ranging from 12 to 31% and reaching 53% with their mixture. The IgE from sera of olive-allergic patients showed a significant diversity of binding capacity to the members of the Ole e 1-like family due to the microheterogeneity of their polypeptide sequences, in spite of their highly conserved primary structures. Whereas one of the isoforms of Ole e 1 exhibits a highly similar behavior to the natural form, being a putative molecule for diagnostic purposes, other ones can be considered as hypoallergenic variants of this allergen and, thus, potential candidates to be used in immunotherapy.
González
Eva M
EM
Departamento de Bioquímica y Biología Molecular, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
Villalba
Mayte
M
Lombardero
Manuel
M
Aalbers
Marja
M
van Ree
Ronald
R
Rodríguez
Rosalía
R
D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D052179:Antigens, Plant; D000939:Epitopes; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology*; D011134:Polysaccharides / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D020033:Protein Isoforms; D011994:Recombinant Proteins / Q000276:immunology
D000485:Allergens; D000911:Antibodies, Monoclonal; D052179:Antigens, Plant; D000939:Epitopes; D007074:Immunoglobulin G; C081946:Ole e I protein, Olea europaea; D010940:Plant Proteins; D011134:Polysaccharides; D020033:Protein Isoforms; D011994:Recombinant Proteins; D007073:Immunoglobulin E