Cell culture HK-2 cells (human renal proximal tubular epithelial cells immortalized by transduction with human papilloma virus 16 E6/E7 genes) were purchased from American Type Culture . The effect of PBMCs on the activation of extracellular regulated kinase 1 and 2 (ERK1/2) of HK-2 cells. HK cells were cocultured with PBMCs for 24 hrs following TGF-b 1 (0.1 ng/ml) stimulation for 24 hrs (TGF-b 1 (0.1)-PBMCs). After 4 and 12 hrs of co-culture with PBMCs, aliquots of HK-2 cell lysate were subjected to western blot analysis. For blocking the interaction of LFA-1 and ICAM-1, before coculture, PBMCs were pre-incubated with anti-LFA-1 mAb for 20 minutes (Anti-LFA-1 mAbs) and HK-2 cells were pre-incubated with anti-ICAM-1 mAb for 20 minutes (Anti-ICAM-1 mAbs) or isotype control mAb for 20 minutes (Isotype mAb). HK-2 cells without co-culture with PBMCs following TGF-b 1 (0.1 ng/ml) stimulation for 24 hrs (TGF-b 1 (0.1)) and HK-2 cells without stimulation of TGF-b 1 co-cultured with PBMCs (PBMCs) were investigated as controls. One representative immunoblot is presented at the top of the graph. doi:10.1371/journal.pone.0023267.g007