D1.281 - Development of a Peanut-Specific Human Mast Cell Assay for Screening Probiotics and other Nutritional Components with Anti-Allergic Potential

Mast cell activation is a hallmark of allergic responses, yet robust in vitro models for screening nutritional components with anti-allergic potential remain limited. We established a peanut-specific human mast cell assay to evaluate the inhibitory effect of Bifidobacterium breve on allergen-induced degranulation, measured by β-hexosaminidase release.

Human mast cells were (HMCs) differentiated from CD34⁺ progenitors isolated from peripheral blood mononuclear cells of healthy donors. Cells were cultured for 4 weeks in StemSpan SFEM II medium supplemented with IL-6, IL-3, and stem cell factor, followed by maturation in IMDM GlutaMAX I with additional growth factors. After 8 weeks, mast cell maturity was confirmed, and cells aged 12–36 weeks were used for experiments.

Mature HMCs were sensitized with plasma from a peanut-allergic donor for 4 hours, then incubated for 24 hours with different amounts of Bifidobacterium breve (B. breve). Following washing, cells were crosslinked with peanut allergens Ara h 2/h 6 for 1.5 hours, and β-hexosaminidase release was quantified. 

HMC : B. breve ratios in the range of 1:3 to 1:30 dose dependently inhibited HMC degranulation. Ratios of 1:3, 1:10 and 1:30 inhibited beta hexosaminidase release with a maximum of 9,8%, 12,1% and 19,6% respectively. At higher ratios (1:50, 1:100 and 1:200) no difference in inhibition of beta hexosaminidase release was found, indicating that at a certain concentration the effect of B. breve is optimal and cannot be further enhanced.

This peanut-specific human mast cell assay offers a robust in vitro platform to assess the anti-allergic potential of B. breve and potentially other probiotics and nutritional components. Using this model, B. breve demonstrated a dose-dependent inhibitory effect on allergen-induced mast cell degranulation. These findings highlight the assay’s utility for screening other probiotics and nutritional interventions aimed at mitigating allergic responses.