A Novel Approach to Specific Allergy Treatment: The Recombinant Allergen-S-Layer Fusion Protein rSbsC-Bet v 1 Matures Dendritic Cells That Prime Th0/Th1 and IL-10-Producing Regulatory T Cells

Abstract

An ideal vaccine for allergen-specific immunotherapy of type I allergies should display reduced mediator-releasing capacity, induce maturation of APC, and modify the disease-eliciting Th2-dominated allergen-specific response to a more physiological response. We have previously shown that rSbsC-Bet v 1, the recombinant fusion protein of a bacterial surface (S-layer) protein of Geobacillus stearothermophilus ATCC 12980 and the major birch pollen allergen Bet v 1, exhibited reduced allergenicity and induced IFN-γ and IL-10 synthesis in Bet v 1-specific Th2 clones. In this study, we characterized the effects of rSbsC-Bet v 1 on immature monocyte-derived dendritic cells (mdDC) and the consequences for the polarization of naive CD4+ T lymphocytes isolated from the blood of birch pollen-allergic patients. mdDC responded to rSbsC-Bet v 1 with a significant up-regulation of costimulatory molecules, functional maturation, and the synthesis of IL-10 and IL-12. mdDC matured with rSbsC-Bet v 1 induced the differentiation of naive T cells into IFN-γ-producing cells. This effect was IL-12 dependent. In parallel, a substantial number of naive T cells developed into IL-10-producing CD25+Foxp3+CLTA-4+ cells capable of active suppression. Thus, rSbsC-Bet v 1 showed immune stimulatory capacity on DC, which then promoted the simultaneous differentiation of Th0/Th1 cells and regulatory T cells. These data further support that the concept of conjugating allergens to bacterial agents is a promising approach to improve vaccines for specific immunotherapy of atopic allergies.

Grass pollen immunotherapy induces Foxp3-expressing CD4+CD25+ cells in the nasal mucosa

“…13,28 In studies of cells derived from peripheral blood of subjects with birch allergy, a recombinant Bet v 1 allergen-S-layer fusion protein primed the development of naive T cells into IL-10-producing CD25 1 Foxp3 1 CLTA4 1 cells capable of active suppression. 29 Functionally active, antigen-specific Foxp3 1 CD4 1 CD25 1 T cells have also been identified in peripheral blood of atopic and nonatopic individuals. 30 The mechanisms of suppression by Treg subsets remain controversial; both cell-cell contact and downregulation through the immunosuppressive cytokines IL-10 and TGF-b have been described.…”

“…The study was performed with approval of the ethics committee of the Royal Brompton Hospital and with the informed consent of the participants. The patients comprised 13 untreated subjects with grass pollen allergy ( [29][30][31][32][33][34] years]) received placebo injections. GP-IT (Alutard SQ Phleum pratense, ALK-Abelló) or placebo injections were administered during a clustered 4-week updosing phase, followed by monthly maintenance injections (containing 20 mg of the major allergen Phl p 5) for 2 years.…”

Differential T-cell responses and allergen uptake after exposure of dendritic cells to the birch pollen allergens Bet v 1.0101, Bet v 1.0401 and Bet v 1.1001

“…The addition of TNF-a and IL-1b in combination with allergens was used in previous studies for DC maturation (Bellinghausen et al 2008;Konig et al 2007;Shreffler et al 2006). The requirement of such a stimulus to certain allergens to induce DC maturation was demonstrated as stimulation of DCs by Bet v 1 or Der p 1 alone did not result in DC maturation and T-cell proliferation (De Wit et al 2000;Gerstmayr et al 2007). Interestingly, HLA-DR expression was in general higher for allergic than non-atopic individuals (Fig.…”

Naturally processed T cell–activating peptides of the major birch pollen allergen

“…28 DCs were homogenized in 10 mmol/L TRIS acetate pH7 containing sucrose (250 mmol/L), and microsomes were isolated by ultracentrifugation. 29 Bet v 1 (5 mg) was digested with microsomal enzymes (7 mg) in 100 mmol/L citrate buffer pH 4.8 containing dithiothreitol (2 mmol/ L) at 378C.…”