Dendritic cell characteristics on THP-1 after co-culture with lactobacilli. (A) Flow cytometric results showed CD40, CD80, CD1a, CD83, and HLA-DR expression on THP-1 cells stimulated with different species of Lactobacillus (L. crispatus, L. fermentum, L. jensenii, L. gasseri, L. delbrueckii1, and L. johnsonii) compared with unstimulated THP-1 cells. The percentages of positive cells in each analysis measured by MFI (mean fluorescence intensity) are presented. (B) Detection of THP-1 endocytic activity after stimulation with L. crispatus and L. fermentum. FITC-conjugated dextran positive cells were detected by flow cytometry. (C) Mixed lymphocyte reaction (MLR) analysis of THP-1 stimulated by L. crispatus and L. fermentum. 100 μl THP-1 cells (1 × 105, 1 × 106, and 1 × 107) treated with L. crispatus and L. fermentum and 100 μl CD4+ T cells (1 × 105) stained with CFSE were mixed in a 96-well plate and co-cultured for 6 day. The MFI were measured by flow cytometry and the results were recorded as the mean±SD from triplicate wells. (D) Intracellular cytokines of THP-1 after stimulation with L. crispatus and L. fermentum. THP-1 cells activated by L. crispatus and L. fermentum were harvested and stained with Th1- or Th2-associated cytokines (IFN-γ, TNF-α, IL-12, IL-4, and IL-10) kit.