New developments in immunotherapies for food allergy

Peptide Glycodendrimers as Potential Vaccines for Olive Pollen Allergy

Olive pollen is one of the most important causes of respiratory allergy, with Ole e 1 being the most clinically relevant sensitizing allergen. Peptide-based vaccines represent promising therapeutic approaches, but the use of adjuvants is required to strengthen the weak immunogenicity of small peptides. We propose the use of dendrimeric scaffolds conjugated to the T cell immunodominant epitope of Ole e 1 (OE_109-130) for the development of novel vaccines against olive pollen allergy. Four dendrimeric scaffolds containing an ester/ether with nine mannoses, an ester succinimidyl linker with nine N-acetyl-glucosamine units or nine ethylene glycol units conjugated to OE_109-130 peptide were designed, and their cytotoxicity, internalization pattern, and immunomodulatory properties were analyzed in vitro. None of the dendrimers exhibited cytotoxicity in humanized rat basophil (RBL-2H3), human bronchial epithelial Calu-3, and human mast LAD2 cell lines. Confocal images indicated that mannosylated glycodendropeptides exhibited lower colocalization with a lysosomal marker. Moreover, mannosylated glycodendropeptides showed higher transport tendency through the epithelial barrier formed by Calu-3 cells cultured at the air-liquid interface. Finally, mannosylated glycodendropeptides promoted Treg and IL10⁺Treg proliferation and IL-10 secretion by peripheral blood mononuclear cells from allergic patients. Mannosylated dendrimers conjugated with OE_109-130 peptide from Ole e 1 have been identified as suitable candidates for the development of novel vaccines of olive pollen allergy.

T cell epitope of arginine kinase with CpG co-encapsulated nanoparticles attenuates a shrimp allergen-induced Th2-bias food allergy

T cell peptide-based immunotherapy (PIT) is an appealing therapeutic strategy for modulating allergic responses without IgE cross-linking. We propose a novel PIT that combines a T-cell epitope of the shrimp allergen arginine kinase (AKp) with TLR9 agonist CpG-ODN in nanoparticles (CpG-AKp NPs) to attenuate a shrimp allergen-induced food allergy. Treatment with CpG-AKp NPs demonstrated the attenuation of anaphylaxis responses such as the reduced incidence of diarrhea and hypothermia, lower levels of specific IgE and the induction of IgG2a in serum. Th2 cytokines were suppressed and higher Th1 cytokines were detected in the splenocyte culture supernatants. Treatment of CpG-AKp NPs also enhanced the protein expression of Foxp3 and IL-10 in small intestine but decreased the activation of STAT6 and GATA3 expression, which are related to differentiation of Th2. Our data indicated that CpG-AKp NPs may represent a promising PIT against shrimp allergy.

Co-delivery of allergen epitope fragments and R848 inhibits food allergy by inducing tolerogenic dendritic cells and regulatory T cells

BACKGROUND

Food allergy (FA) is a significant public health problem. The therapeutic efficacy for FA is unsatisfactory currently. The breakdown of intestinal immune tolerance is associated with the pathogenesis of FA. Therefore, it is of great significance to develop novel therapeutic methods to restore immune tolerance in treating FA.

METHODS

We proposed an oral administration strategy to treat FA by co-delivering food allergen epitope fragment (peptide: IK) and adjuvant R848 (TLR7 ligand) in the mPEG-PDLLA nanoparticles (PPLA-IK/R848 NPs). The generation of tolerogenic dendritic cells (DCs) and regulatory T cells (Tregs) induced by PPLA-IK/R848 NPs were evaluated in vitro and in vivo. The therapeutic effects of PPLA-IK/R848 NPs were also assessed in an OVA-induced FA model.

RESULTS

PPLA-IK/R848 NPs could efficiently deliver IK to DCs to drive DCs into the tolerogenic phenotypes and promote the differentiation of Tregs in vitro and in vivo, significantly inhibited FA responses through the recovery of intestinal immune tolerance.

CONCLUSION

Oral administration of PPLA-IK/R848 NPs could efficiently deliver IK and R848 to intestinal DCs and stimulate DCs into allergen tolerogenic phenotype. These tolerogenic DCs could promote the differentiation of Tregs, which significantly protected mice from food allergic responses. This study provided an efficient formulation to alleviate FA through the recovery of immune tolerance.