Fig. 7.
Characterization of HL-1cure cells. (A) Expression of CAR mRNA in HL-1cure cells. Total RNA was isolated from HL-1cure cells at the indicated passages after CVB3 infection, and CAR mRNA expression was quantified by real-time RT-PCR. CAR mRNA expression of noninfected HL-1 cells was set as 100%. (B) Western blot analysis of CAR, SERCA2a, and GAPDH expression in HL-1 and HL-1cure cells. Compared to HL-1 cells, HL-1cure cells showed decreased CAR expression but retained a similar level of expression of the SERCA2a cardiomyocyte-specific protein. (C) Resistance of HL-1cure cells to CVB3 and CVB3-HL1 infection. HL-1 and HL-1cure cells were infected with CVB3 and CVB3-HL1 at an MOI of 1. Virus titers in the cell culture supernatant were quantified by plaque assays 24 h later. Both viruses showed a significant decrease of replication in HL-1cure cells compared to HL-1 cells. Values are given as means ± SD of the results of two independent experiments, each performed in duplicate. (D) HL-1cure cells resist CVB3-HL1-induced cell lysis. HL-1 and HL-1cure cells were seeded in 96-well plates and infected with different doses of CVB3-HL1. Cell viability was measured by a cell proliferation assay (XTT), with uninfected cells (mock) as a control (set as 100%). HL-1cure cells, but not HL-1 cells, resisted CVB3-HL1-induced cell lysis. Values are given as means ± SD of the results of two experiments, each performed in quadruplicate.