Subsequent infection with Wt virus, followed by fixation at 16 h and staining for ICP4 showed that spread of HSV1 in nTERT or KO cells was not altered in cells depleted of HVEM or PTP1B (Fig 6D), and therefore the nectin1-independent spread pathway that functions in KO cells does not appear to involve either of these previously identified factors. This evidence concerns the gene PTPN1 and infection.