Hypoallergenic Der p 1/Der p 2 combination vaccines for immunotherapy of house dust mite allergy.
BACKGROUND
More than 50% of allergic patients have house dust mite (HDM) allergy. Group 1 and 2 allergens are the major HDM allergens.


OBJECTIVE
We sought to produce and perform preclinical characterization of a recombinant hypoallergenic combination vaccine for specific immunotherapy of HDM allergy.


METHODS
Synthetic genes coding for 2 hybrid proteins consisting of reassembled Der p 1 and Der p 2 fragments with (recombinant Der p 2 [rDer p 2]/1C) and without (rDer p 2/1S) cysteines were expressed in Escherichia coli and purified to homogeneity by means of affinity chromatography. Protein fold was determined by using circular dichroism analysis, allergenic activity was determined by testing IgE reactivity and using basophil activation assays, and the presence of T-cell epitopes was determined based on lymphoproliferation in allergic patients. Mice and rabbits were immunized to study the molecules' ability to induce an allergic response and whether they induce allergen-specific IgG capable of inhibiting allergic patients' IgE binding to the allergens, respectively.


RESULTS
rDer p 2/1C and rDer p 2/1S were expressed in large amounts in E coli as soluble and folded proteins. Because of the lack of disulfide bonds, rDer p 2/1S did not form aggregates and was obtained as a monomeric protein, whereas rDer p 2/1C did form aggregates. Both hypoallergens lacked relevant IgE reactivity and had reduced ability to induce allergic inflammation and allergic responses but induced similar T-cell proliferation as the wild-type allergens. Immunization with the hypoallergens (rDer p 2/1S > rDer p 2/1C) induced IgG antibodies in rabbits that inhibited the IgE reactivity of patients with HDM allergy to Der p 1 and Der p 2.


CONCLUSIONS
The preclinical characterization indicates that particularly rDer p 2/1S can be used as a safe hypoallergenic molecule for both tolerance and vaccination approaches to treat HDM allergy.
Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
Kuan-Wei
KW
Chen
Katharina
K
Blatt
Wayne R
WR
Thomas
Ines
I
Swoboda
Peter
P
Valent
Rudolf
R
Valenta
Susanne
S
Vrtala
D000818:Animals; D039741:Antigens, Dermatophagoides / Q000235:genetics / Q000276:immunology*; D060829:Arthropod Proteins / Q000235:genetics / Q000276:immunology*; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D004926:Escherichia coli; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000517:prevention & control*; D007073:Immunoglobulin E / Q000276:immunology / Q000378:metabolism; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D011485:Protein Binding; D039981:Pyroglyphidae / Q000235:genetics / Q000276:immunology*; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D014611:Vaccination; D014612:Vaccines / Q000235:genetics / Q000276:immunology* / Q000627:therapeutic use; D017778:Vaccines, Combined; D014614:Vaccines, Synthetic
D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; C451163:Dermatophagoides pteronyssinus antigen p 2; D018984:Epitopes, T-Lymphocyte; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins; D014612:Vaccines; D017778:Vaccines, Combined; D014614:Vaccines, Synthetic; D007073:Immunoglobulin E; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1