Aurintricarboxylic acid increases yield of HSV-1 vectors

Pechan, Peter; Ardinger, Jeffery; Ketavarapu, Jyothi; Rubin, Hillard; Wadsworth, Samuel C; Scaria, Abraham

Effect of ATA on wild-type HSV-1 titers in culture The effects of ATA on DRP/ml viral titers of wild-type (wt) HSV-1 strains (KOS and McIntyre) were tested when propagated in HEK-293 or Vero cells using the 50 µmol/l ATA@step1 protocol (Figure 3a) . In Vero cells, one-way analysis of variance and Tukey's multiple comparison test have shown that ATA significantly increased (***P < 0.001; n = 4) only the KOS strain DRP/ml titers; from 1.7 ± 1.1 × 10 8 DRP/ml (−ATA) to 9.1 ± 2.1 × 10 8 DRP/ml (+ATA) (Figure 3a ). The McIntyre virus "+ ATA" titers were also elevated, from 2.6 ± 1.5 × 10 8 DRP/ml (−ATA) to 5.8 ± 1.1 × 10 8 DRP/ml (+ATA), but according analysis of variance, the difference was not significant (P > 0.05; n = 4); (Figure 3a ). On the contrary, in HEK-293 cells, only McIntyre strain titers were significantly increased (***P < 0.001; n = 4) by ATA, from 1.4 ± 0.8 × 10 8 DRP/ml (−ATA) to 1.2 ± 0.5 × 10 9 DRP/ml (+ATA) (Figure 3a ). The titers of KOS strain in HEK-293 cells, on the other hand, even dropped, from 1.1 ± 0.9 × 10 8 DRP/ml (−ATA) to 5.5 ± 4.9 × 10 7 DRP/ml (+ATA), but according analysis of variance, the difference was not significant (P > 0.05; n = 4) (Figure 3a ). In a larger study (n = 10) conducted in six-well plates, two-way analysis of variance and Sidak's multiple comparison test have shown that ATA significantly increased (**P < 0.01; n = 10) ICP27-deficient vector rHSV-enhanced green fluorescent protein (EGFP) (d27-GFP) DRP/ml titers in V27 cells, from 5.4 ± 2.7 × 10 7 to 3.3 ± 1.2 × 10 8 DRP/ml and that DRP/ml titers of wtHSV-1 McIntyre strain in HEK-293 cells have significantly increased from 1.1 ± 0.5 × 10 8 to 1.0 ± 0.3 × 10 9 DRP/ml (***P < 0.001) (Figure 3b ).