RANTES promoter activity by luciferase assay. Analysis of RANTES promoter activity in (A) HepG2 and (B) Chang Liver (CHL) cell lines constitutively transfected with empty vector (Hepswx and CHWT), or expressing HCV core protein (Hep39 and CH39) or C-E1-E2-NS2-NS3 (Hep352 and CH352). Results are expressed as the relative light units (RLU) of luciferase activity in each cell extract that was equalized for each sample. Data shown are the means of two independent transfections and three aliquots of cell extracts were analyzed in each experiment. The standard deviation is indicated by the error bars; statistical significance (p < 0.05) was determined by Student's t-test for differences.