Ex vivo autologous immune cell assay to study modulation of type 2 Inflammation by processed- or novel food extracts in peanut allergy

Abstract

Peanut allergy represents a major food-allergy burden, raising concerns about food processing and novel dietary products. Current diagnostics assess primarily allergic endpoints rather than immune mechanisms initiating and maintaining type 2 inflammation, particularly DC2-mediated Th2 polarization. Here, an ex vivo autologous type 2 inflammatory monocyte-derived dendritic cell (moDC) DC2/T cell and B cell assay has been introduced enabling to study immunomodulatory effects induced by unprocessed (P-D) versus processed (P-DH (heated) or P-DHG (heated and glycated)) peanut proteins. Separately, different emerging food samples were assessed (protein concentrates or whole biomass) enabling to study their capacities to modify inflammatory DC2/T cell responses. CD14+ monocytes, CD4+ T cells and CD19+ B cells were isolated from six peanut-allergic patients' PBMCs. MoDCs generated with IL4/GM-CSF were exposed (48h) to type 2 polarizing cytokine (DC2) mix, or DC2 mix combined with the food samples. Next, DC2s were co-cultured with T cells (5d), followed by B cells incubation with DC2/T cell supernatant and food samples (10d). Supernatants and cells were analyzed for Th1/Th2/Th-regulatory (Treg) cells, IgE and IgG profiles. DC2 induced a strong Th2 phenotype and activity, P-D DC2 further enhanced IL13 secretion and %Tregs. P-DH DC2 favored Th2, whereas P-DHG DC2 increased IFN{gamma}, with neither increasing %Treg. All increased CD40L+CD25+ memory Th2 cells. Wheat, whey and seaweed biomass had little effect on DC2/Th2 driven type 2 inflammation at the dose studied, whereas algae showed distinct immunomodulatory, adjuvant-like activity upon co-exposure during inflammatory DC2 maturation. In conclusion, this autologous in vitro assay captures modification of type 2 inflammatory response in DC2-Th2 interaction, which can compile both allergen-specific and generic reactivity to food samples, supporting the potential future use of this assay as an additional tool to assess type 2-driving potential and possible allergenicity of emerging foods and processing methods in peanut-allergic patients.