Identification of an immunodominant IgE epitope of the Parietaria judaica major allergen.
Par j 1.0101 is one of the two major allergens of the Parietaria judaica (Pj) pollen, and its three-dimensional structure was built by three-dimensional structural homology modeling. The resultant model was used to identify putative IgE binding regions. Western blot analysis of gene fragmentation products showed that the 1 to 30 region was capable of binding specific IgE from a pool of sera (n = 30) of patients allergic to Pj pollen. Using the structural model as a guide, deletion and site-directed mutagenesis of the 1 to 30 region was performed, and the amino acids involved in IgE binding were identified. In addition, a synthetic peptide covering the 1 to 30 region was capable of binding human IgE without triggering histamine release from basophils of Pj allergic patients (n = 6) and thus represents a haptenic molecule with potential use as an immunotolerant agent. This epitope is also present on the Par j 2.0101 major allergen representing a common IgE epitope. It is an immunodominant epitope, since it was capable of inhibiting 30% of all specific IgE against the Pj major allergens, and therefore, it might be a candidate for the future development of immunotherapeutics.
Colombo
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P
Istituto di Biologia dello Sviluppo Consiglio Nazionale Delle Ricerche, Palermo, Italy. colombo@ibs.pa.cnr.it
Kennedy
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D
Ramsdale
T
T
Costa
M A
MA
Duro
G
G
Izzo
V
V
Salvadori
S
S
Guerrini
R
R
Cocchiara
R
R
Mirisola
M G
MG
Wood
S
S
Geraci
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D
D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000595:Amino Acid Sequence; D018604:Epitope Mapping; D006636:Histamine Release; D006801:Humans; D016056:Immunodominant Epitopes; D007073:Immunoglobulin E / Q000276:immunology*; D008961:Models, Structural; D008969:Molecular Sequence Data; D011058:Pollen / Q000276:immunology*
D000485:Allergens; D016056:Immunodominant Epitopes; D007073:Immunoglobulin E