Immunological characterization of a Blo t 12 isoallergen: identification of immunoglobulin E epitopes.
BACKGROUND
Differences in the IgE response to isoallergens could have clinical implications; therefore, its analysis will contribute to the design of better strategies for the diagnosis and treatment of allergic respiratory diseases. Several isoforms have been described from mites but there is no information about the clinical impact of Blomia tropicalis isoallergens.


OBJECTIVE
To evaluate the differences in the IgE response against two Blo t 12 isoallergens.


METHODS
The IgE-binding properties of Blo t 12 isoallergens were analysed by ELISA, a skin prick test and ELISA cross-inhibition. Epitope mapping was performed using synthetic overlapping peptides. Fold recognition methods were used to model the chitin-binding domain of the two isoallergens.


RESULTS
The frequency and strength of the IgE response were greater for Blo t 12.0101 than for Blo t 12.0102. Three IgE-binding areas were identified in Blo t 12.0101; one of them included two residues that are different in Blo t 12.0102. Modelling of the chitin-binding domains of these allergens predicted that they have structural differences that could influence antibody recognition of one of these epitopes.


CONCLUSIONS
In silico structural analysis and immunological characterization of Blo t 12 reveals that allergen polymorphism influences IgE reactivity. Blo t 12.0101 is the most IgE-reactive isoform in Cartagena. The identified IgE epitopes could be mutated to obtain hypoallergenic molecules of potential use for immunotherapy.
Zakzuk
J
J
Institute for Immunological Research, University of Cartagena, Cartagena, Colombia.
Jiménez
S
S
Cheong
N
N
Puerta
L
L
Lee
B W
BW
Chua
K Y
KY
Caraballo
L
L
D000293:Adolescent; D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D001249:Asthma / Q000276:immunology*; D002648:Child; D003001:Cloning, Molecular; D003429:Cross Reactions / Q000276:immunology; D018604:Epitope Mapping; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology; D020033:Protein Isoforms / Q000737:chemistry / Q000276:immunology; D039981:Pyroglyphidae / Q000737:chemistry / Q000276:immunology*; D016415:Sequence Alignment; D012882:Skin Tests
D000485:Allergens; D010455:Peptides; D020033:Protein Isoforms; D007073:Immunoglobulin E