Table 1.
Characteristics of genotype 1–6 sf-HCVcc virus stocks compared to HCVcc reference stocks
| Peak HCV infectivity titerb log10FFU/mL |
Peak HCV RNA titerc log10IU/mL |
Peak HCV Core titerd log10 pmol Core/mL |
Specific infectivitye FFU/IU |
Specific infectivityf FFU/pmol Core |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Isolate (genotype)a | sf-HCVcc | HCVcc | sf-HCVcc | HCVcc | sf-HCVcc | HCVcc | sf-HCVcc | HCVcc | sf-HCVcc | HCVcc |
| H77(1a) | 5.0 | 4.3 | 7.6 | 7.5 | 5.7 | 5.4 | 1/316 | 1/1,585 | 1/4.8 | 1/13.5 |
| J4(1b) | 4.7 | 3.2 | 7.5 | 7.3 | 5.6 | 5.1 | 1/631 | 1/12,589 | 1/8.1 | 1/79.8 |
| J6(2a) | 5.6 | 5.0 | 7.6 | 7.6 | 5.5 | 5.5 | 1/100 | 1/398 | 1/0.8 | 1/3.4 |
| S52(3a) | 4.9 | 4.3 | 7.4 | 7.2 | 5.5 | 5.4 | 1/316 | 1/794 | 1/3.8 | 1/12.5 |
| ED43(4a) | 4.7 | 3.6 | 7.1 | 7.6 | 5.0 | 5.4 | 1/251 | 1/10,000 | 1/2.0 | 1/58.0 |
| SA13(5a) | 6.2 | 4.1g | 7.8 | 7.0 | 5.5 | 4.9 | 1/40 | 1/794 | 1/0.2 | 1/6.6 |
| HK6a(6a) | 5.6 | 4.0 | 7.7 | 7.7 | 5.6 | 4.8 | 1/126 | 1/1,000 | 1/0.9 | 1/5.9 |
Serum-free cultures were infected and maintained as described in Materials and Methods (Figure 2). For sf-HCVcc, supernatant HCV infectivity titers, Core antigen, and RNA titers were determined, and specific infectivities was calculated. Representative peak infectivity titers as well as Core and RNA titers from the same sample are shown. Core-E2 sequences were determined by direct sequence analysis as described in Materials and Methods. For sf-J6(2a), sf-S52(3a), sf-ED43(4a), sf-SA13(5a) and sf-HK6a(6a), Core-E2 sequences were identical to the plasmid sequence. The sf-H77(1a) had acquired the previously described amino acid change Y361H, estimated to be present in 50% of viral genomes; this change was also present in the H77(1a) HCVcc stock shown in this table [11]. The sf-J4(1b) had acquired amino acid changes T578A and D584G, estimated to be present in the majority of viral genomes. For HCVcc, characteristics of references stocks (HCVcc ref. stocks) are reproduced from Gottwein et al. 2009 [11].
Isolate and genotype of Core-NS2 of the used JFH1-based recombinants is indicated. Recombinants are further described in Materials and Methods.
For sf-HCVcc, supernatant infectivity titers were determined as FFU/mL by a cell culture-based titration assay as described in Materials and Methods. Values are means of three replicates. Iw HCVcc, values are reproduced from [11].
For sf-HCVcc, supernatant RNA titers were determined in the samples, for which infectivity titers are given, as IU/mL by Taq-Man PCR as described in Materials and Methods. Values are means of two replicates. For HCVcc, values are reproduced from [11].
Core titers were determined in the samples for which infectivity titers are given, as pmol/mL using the ARCHITECT HCV Ag assay (Abbott).
For sf-HCVcc, specific infectivity was calculated as FFU/IU by dividing supernatant infectivity titers with the corresponding RNA titers. For HCVcc, values were adapted from [11] to FFU/IU by dividing supernatant infectivity titers with the corresponding RNA titers.
Specific infectivity was calculated as FFU/pmol Core by dividing supernatant infectivity titers with the corresponding Core titers.
The peak infectivity titer of this SA13(5a) reference stock was lower than what we typically observe. Typically, peak titers for SA13(5a) are ~5 log10 FFU/mL (Figure 3A).