Modulating allergic response by engineering the major Parietaria allergens

Clinical studies have demonstrated that long-term clinical improvement is associated with humoral and cellular modifications, such as a decrease in effector cells in target organs and a marked increase in IgG antibodies and in regulatory T (Treg) and B cells.1 In recent years, novel immunotherapy strategies, such as the design of standardized recombinant hypoallergenic derivatives, have been tested in clinical trials, showing that the AIT strategy of reducing allergic adverse events represents a promising therapeutic approach.2 Parietaria judaica (Pj) pollen allergenic components (Par j 1 and Par j 2) have been investigated, showing that they belong to lipid transfer proteins, one of the most relevant families of allergenic proteins in pollen and plant-derived food.3 Engineered hybrids of the 2 major Parietaria allergens have been already developed to obtain hypoallergenic molecules potentially applicable to allergy immunotherapy.4 Our research group developed strategies to design and characterize a novel engineered hybrid composed of the 2 major Parietaria allergens (PjEDcys) with reduced allergenicity but retained immunogenicity in both murine and human models.5 In this scenario, we decided to study the modulation of the immunologic response of the disulphide bonds PjEDcys hybrid (Fig 1, A) in PBMCs from Parietaria-allergic patients and in a mouse sensitization model.[...]the in vivo therapeutic study demonstrates the capability of the engineered hybrid to modulate the pre-existing sensitization toward a protective humoral response.Carboxyfluorescein succinimidyl ester proliferation assay PBMCs from 10 P judaica-allergic patients were prepared from blood from Parietaria-allergic donors by standard Ficoll density gradient separation and resuspended in 1x PBS, pH 7.2 (1 x 107 cells/mL), and labeled with a solution containing 5 μM carboxy-fluorescein diacetate succinimidyl ester (Molecular Probe) as previously described.E1 Cells were incubated with the antigens (rPar j 1 plus rPar j 2 [Mix] and rPjEDcys) at a concentration of 1 and 10 μg/mL for 7 days.Patient 1 μg/mL, P = .906 10 μg/mL, P = .386 rPar j 1 + rPar j 2 rPjEDcys rPar j 1 + rPar j 2 rPjEDcys 1 0.1 0.1 0.3 0.6 2 0.4 0.2 1.3 1.1 3 0.6 0 1.4 0 4 0.5 0.2 1 1.1 5 0 0.3 0.2 0.3 6 0.2 0.9 0.3 1.3 7 0 0.1 0.5 0.6 8 0.1 0.4 3.2 1.5 9 0.4 0.1 1.5 0.7 10 0.1 0.3 1.1 0.4 Median and IQR 0.15 (0.10-0.40) 0.20 (0.10-0.30) 1.05 (0.30-1.40) 0.65 (0.40-1.10) 1 H.J. Hoffmann, E. Valovirta, O. Pfaar, P. Moingeon, J.