Expression of HHV-6 mRNA in SAS413 and SAS527. (A) Expression of the HHV-6 immediate-early gene in the cell lines was examined by RT-PCR. cDNA synthesized from cord blood mononuclear cells (lane 1), SAS413 (lane 2), and SAS527 (lane 3) inoculated with HHV-6A or HHV-6B was amplified using primers corresponding to the immediate-early gene. (B) RT-PCR for β-actin gene. Lane M shows marker DNAs.