Direct effects of activated lung cancer cells or their mediators on peripheral blood mononuclear cells (PBMCs) measured during the co-culture of PBMCs from healthy donors with lung cancer cells (A549) or the supernatant pre-stimulated with lipopolysaccharide (LPS), respectively. A549 cells were stimulated with LPS at 10, 100, 1000 ng/ml or vehicle for 24 hrs, and then LPS-stimulated A549 cells as activated LC cells and their supernatant as activated medium were harvested. After then, PBMCs from healthy donors were co-cultured with the harvested activated or non-activated A549 cells and medium for 48 hrs, respectively. The control group was PBMC from healthy donors without co-culture. A: Frequency of CD4+ T cells in total PBMCs, B: Frequency of CD19+ B cells in total PBMCs, C: Frequency of Tregs in CD4+ T cells, D: Frequency of CD45RA+Tregs in CD4+ T cells, E: Frequency of CD19+CD24hiCD27+ B cells in CD19+ B cells, and F: Frequency of CD19+IL-10+ B cells in CD19+ B cells. +, ++, and +++ stand for p values less than 0.05, 0.01, and 0.001, as compared with corresponding controls including vehicle-stimulated PBMC, PBMC co-culture with vehicle-stimulated A549 supernatant, or PBMC co-culture with vehicle-stimulated A549 cells, respectively. *, **, and *** stand for p values less than 0.05, 0.01, and 0.001, as compared with corresponding LPS-stimulated PBMC, respectively.