Immunomodulatory bioactivity of soy and milk ferments on monocyte and macrophage models

Fermented products provide a functional food-based approach for probiotic delivery, containing both the bacteria and their potentially bioactive metabolites. This study investigated potential immunomodulatory effects of soy and dairy ferments prepared with Bifidobacterium longum R0175 or Lactobacillus helveticus R0052 in combination with Streptococcus thermophilus ST5 on a human monocyte model (U937). We examined the effects of both soy and dairy ferments on TGF-β1 production by U937 cells challenged with the pro-inflammatory cytokine Tumor Necrosis Factor-α (TNF-α) at either the monocyte stage or the macrophage stage (following differentiation with all-trans retinoic acid). Effects on cell surface markers involved in macrophage activation and adhesion were also examined. Both soy and dairy ferments influenced U937 cytokine production with significant differences seen depending on the U937 differentiation stage. This suggests that potential immunomodulatory effects of fermented products can vary with respect to the target cell type and its stage of differentiation.