Indirect effects of lung cancer cells on peripheral blood mononuclear cells (PBMCs) measured during the co-culture of lung cancer cells (A549) with PBMCs from healthy donors in a transwell model. A549 cells were planted in the lower chamber of the transwell and stimulated with LPS at 100 and 500 ng/ml or vehicle for 24 hrs. PBMCs from healthy donors were then added to the upper chamber of the transwell for co-culture for 48 hrs. 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; (F) Frequency of CD19+IL-10+ B cells in CD19+ B cells. * stand for p values less than 0.05, as compared with the control group with PBMC from healthy donors without co-culture.