Yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 and Streptococcus thermophilus OLS3059 enhances dendritic cell activity and reduces cold-like symptoms in healthy adults: A randomized controlled trial

The immunomodulatory effects of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 and Streptococcus thermophilus OLS3059 were evaluated in a randomized, double-blind, placebo-controlled trial involving 140 healthy males and females. The participants ingested test yogurt or placebo daily for eight weeks. The yogurt group exhibited significantly increased CD86 + and CD80 + conventional dendritic cell (cDC) populations, CD40 + plasmacytoid DC (pDC) populations upon viral antigen stimulation, CD69 expression on CD4 + T cells, and salivary s-IgA levels compared to those in the placebo group. The onset of local (nausea) and systemic (fatigue, general malaise, and feeling somewhat unwell) cold-like symptoms was significantly reduced in the yogurt group compared to that in the placebo group. These results suggest that intake of yogurt fermented with OLL1073R-1 and OLS3059 enhances cDC and pDC activities and subsequently promotes CD4 + T cell activation and salivary s-IgA production, thereby contributing to health maintenance. • Effect of OLL1073R-1- and OLS3059-fermented yogurt on immune function was evaluated. • Intake of the yogurt enhanced the activity of cDCs and pDCs. • Intake of the yogurt enhanced CD4 + T cell activity and salivary s-IgA production. • Intake of the yogurt reduced the onset of subjective cold-like symptoms.