HCVcc particles and HCV E2 glycoprotein bind BDCA-2 and DCIR-transfected or cotransfected COS-7 cells. (A-B) HCVcc particles (A) or E2 glycoprotein (B) binding to mock-transfected and BDCA-2- and DCIR-transfected or cotransfected COS-7 cells. The index of synergism (IS) is indicated at the MFI values showing synergistic effect on HCV/E2 binding to BDCA-2 and DCIR. It was determined from the following formula: the MFI of anti-E2 mAb after binding of HCVcc to COS-7 cells cotransfected with the combination of DCIR and BDCA-2 expression vectors divided by the sum of MFI of anti-E2 mAb after binding of HCVcc to COS-7 cells transfected separately with DCIR and BDCA-2 expression vectors; IS = MFI_{BDCA-2 + DCIR}/(MFI_BDCA-2 + MFI_DCIR). The combinations resulting in the index of synergism > 1.5 were considered as synergistic. Data are mean ± SEM of 3 independent experiments.