Volume 120, Issue 3 , Pages 602-609, September 2007
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.
Conclusion
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.
Clinical implications
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.
Key words: Hybrid proteins, IgE epitope, Parietaria pollen allergy, recombinant hypoallergens, T-cell epitope
Abbreviations used: CD, Circular dichroism, EAST, Enzyme allergosorbent test, NPA, Natural Par j 1-Par j 2 allergen mix, SIT, Allergen-specific immunotherapy, SPT, Skin prick test
Supported by Bial-Arístegui and by grants FIT-090100-2006-67 from the Programa Nacional de Biomedicina (Acción PROFARMA, Ministerio de Industria Turismo y Comercio, Spain) and IT-2005/0000428 from the Programa INNOTEK (Departamento de Industria, Comercio y Turismo, Gobierno Vasco). R.G.-R. is indebted to the Departamento de Industria, Comercio y Turismo and the Departamento de Educación, Universidades e Investigación (Gobierno Vasco) for a predoctoral fellowship.
Disclosure of potential conflict of interest: J. A. Asturias has received grant support from Programa Nacional de Biomedicina, Ministerio de Industria Turismo y Comercio, Spain, and from the Programa INNOTEK, Departamento de Industria, Comercio y Turismo, Gobierno Vasco. A. Martínez has received grant support from Programa Nacional de Biomedicina, Ministerio de Industria, Turismo y Comercio, Spain, and from the Programa INNOTEK, Departamento de Industria, Comercio y Turismo, Gobierno Vasco. I. Ibarrola has received grant support from Programa Nacional de Biomedicina, Ministerio de Industria Turismo y Comercio, Spain, and from the Programa INNOTEK, Departamento de Industria, Comercio y Turismo, Gobierno Vasco. M. C. Arilla has received grant support from Programa Nacional de Biomedicina, Ministerio de Industria Turismo y Comercio, Spain, and from the Programa INNOTEK, Departamento de Industria, Comercio y Turismo, Gobierno Vasco. R. González-Rioja has received support from Programa Nacional de Biomedicina, Ministerio de Industria Turismo y Comercio, Spain, and from the Programa INNOTEK, Departamento de Industria, Comercio y Turismo, Gobierno Vasco, Departamento de Educación, Universidades e Investigación (Gobierno Vasco). The rest of the authors have declared that they have no conflict of interest.
The nucleotide sequences for the hybrid proteins Q1, Q2, and Q3 have been deposited in the GenBank database under accession numbers AM490432, AM490433, and AM490434, respectively.
PII: S0091-6749(07)00872-X
doi:10.1016/j.jaci.2007.04.039
© 2007 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.
Volume 120, Issue 3 , Pages 602-609, September 2007
