FIG 1.

HHV-6 infection of murine and human lymphoid cells. Murine lymphoid M12 cells, stably expressing the human protein CD46 (M12-CD46), parental M12 cell line, and human T cell lines HSB2 and MOLT3, were infected with HHV-6A (A and C) or HHV-6B (B and D) at an MOI of 1. (A and B) mRNA levels of the viral genes U79 (early), U94 (immediate early), and U100 (late) were determined using RT-qPCR and expressed relative to that of murine GAPDH (M12 and M12-CD46) or human GAPDH (HSB2 and MOLT3). (C and D) Genomic DNA levels of the viral gene U41 were determined using qPCR, and means and standard deviations from two independent experiments are presented. (E) Before infection with HHV-6A, M12, M12-CD46, and HSB2 cells were treated with actinomycin D (actD) at 5 μg/ml for 1 h or left untreated (NT). Total RNA was extracted at 8 h postinfection, and U79 mRNA levels were quantified by RT-qPCR. Results are presented as the number of copies per μg of total RNA and are representative of two independent experiments. (F) Primary murine T lymphocytes were enriched from spleens of wild-type (open bars) or CD46ge (closed bars) mice, ConA activated, and infected with HHV-6A at an MOI of 1. mRNA expression of U79 was quantified relative to that of murine GAPDH by RT-qPCR at different time points postinfection. Dotted lines represent the limit of detection of the qPCR system.