Genetically engineered hybrid proteins from Parietaria judaica pollen for allergen-specific immunotherapy.
BACKGROUND
Despite the use of conventional allergen-specific immunotherapy in clinical practice, more defined, efficient, and safer allergy vaccines are required.


OBJECTIVE
The aim of the study was to obtain hypoallergenic molecules by deleting B-cell epitopes, which could potentially be applied to Parietaria judaica pollen allergy treatment.


METHODS
Three hybrid molecules (Q1, Q2, and Q3) derived from fragments of the 2 major P judaica pollen allergens, Par j 1 and Par j 2, were engineered by means of PCR. Hybrid structures were compared with their natural components by means of circular dichroism, and their biologic activities were compared by using T-cell proliferation assays. Their IgE-binding activity was determined with Western blotting, skin prick tests, and enzyme allergosorbent and ELISA inhibition tests.


RESULTS
The hybrid proteins, especially Q2 and Q3, revealed significantly reduced IgE reactivity compared with the natural allergens, as well as with the whole P judaica extract. Furthermore, in vivo skin prick tests showed that the hybrid proteins had a significantly lower potency to induce cutaneous reactions than the whole P judaica extract. Two (Q1 and Q2) of the 3 hybrid proteins induced a comparable T-cell proliferation response as that produced by the whole extract and natural allergens.


CONCLUSIONS
Considering its reduced anaphylactogenic potential, together with its conserved T-cell reactivity, the engineered Q2 protein could be used in safe and shortened schedules of allergen-specific immunotherapy against P judaica pollen allergy.


CONCLUSIONS
Recombinant hybrid Q2 is able to induce T-cell proliferation, thus evidencing a potential therapeutic effect. Its reduced IgE-binding capacity envisages an excellent safety profile.
González-Rioja
Roberto
R
Research and Development Department, Bial-Arístegui, Bilbao, Spain.
Ibarrola
Ignacio
I
Arilla
M Carmen
MC
Ferrer
Angel
A
Mir
Amparo
A
Andreu
Carmen
C
Martínez
Alberto
A
Asturias
Juan A
JA
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000235:genetics / Q000276:immunology; D052179:Antigens, Plant; D001483:Base Sequence; D015153:Blotting, Western; D003888:Desensitization, Immunologic; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D032403:Parietaria / Q000276:immunology*; D010940:Plant Proteins / Q000138:chemical synthesis* / Q000235:genetics / Q000276:immunology; D011058:Pollen / Q000276:immunology; D016133:Polymerase Chain Reaction; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000138:chemical synthesis* / Q000235:genetics / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000517:prevention & control; D012882:Skin Tests
D000485:Allergens; D052179:Antigens, Plant; C105336:PMAI protein, Parietaria judaica; C103299:Par j 2.0101; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E