Reducing allergenicity by altering allergen fold: a mosaic protein of Phl p 1 for allergy vaccination.
BACKGROUND
The major timothy grass pollen allergen, Phl p 1, resembles the allergenic epitopes of natural group I grass pollen allergens and is recognized by more than 95% of grass-pollen-allergic patients. Our objective was the construction, purification and immunologic characterization of a genetically modified derivative of the major timothy grass pollen allergen, Phl p 1 for immunotherapy of grass pollen allergy.


METHODS
A mosaic protein was generated by PCR-based re-assembly and expression of four cDNAs coding for Phl p 1 fragments and compared to the Phl p 1 wild-type by circular dichroism analysis, immunoglobulin E (IgE)-binding capacity, basophil activation assays and enzyme-linked immunosorbent assay competition assays. Immune responses to the derivative were studied in BALB/c mice.


RESULTS
Grass-pollen-allergic patients exhibited greater than an 85% reduction in IgE reactivity to the mosaic as compared with the Phl p 1 allergen and basophil activation experiments confirmed the reduced allergenic activity of the mosaic. It also induced less Phl p 1-specific IgE antibodies than Phl p 1 upon immunization of mice. However, immunization of mice and rabbits with the mosaic induced IgG antibodies that inhibited patients' IgE-binding to the wild-type allergen and Phl p 1-induced degranulation of basophils.


CONCLUSIONS
We have developed a strategy based on rational molecular reassembly to convert one of the clinically most relevant allergens into a hypoallergenic derivative for allergy vaccination.
Ball
T
T
Department of Pathophysiology, Center for Physiology, Pathophysiology and Immunology, Medical University of Vienna, Austria.
Linhart
B
B
Sonneck
K
K
Blatt
K
K
Herrmann
H
H
Valent
P
P
Stoecklinger
A
A
Lupinek
C
C
Thalhamer
J
J
Fedorov
A A
AA
Almo
S C
SC
Valenta
R
R
D000328:Adult; D000368:Aged; D000485:Allergens / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D001491:Basophils / Q000276:immunology / Q000378:metabolism; D003888:Desensitization, Immunologic / Q000379:methods*; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000276:immunology; D005260:Female; D006632:Histamine / Q000096:biosynthesis / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology*; D016133:Polymerase Chain Reaction; D020836:Protein Structure, Quaternary; D011817:Rabbits; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000138:chemical synthesis / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology / Q000517:prevention & control; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; D018984:Epitopes, T-Lymphocyte; D007074:Immunoglobulin G; D010940:Plant Proteins; D011994:Recombinant Proteins; C090396:PHLPI protein, Phleum pratense; D007073:Immunoglobulin E; D006632:Histamine