Suppression of herpes simplex virus 1 in MDBK cells via the interferon pathway.
Herpes simplex virus (HSV) normally undergoes productive infection in culture, causing cell destruction and plaque formation. Here we characterize an unusual pattern of HSV type 1 (HSV-1) infection in MDBK cells which surprisingly results in suppression of replication, cell recovery, and maintenance of virus. Compared to Vero cells, MDBK cells supported a normal productive infection at a high multiplicity with complete cell destruction. At low multiplicity, HSV also showed an identical initial specific infectivity in the two cell types. Thereafter, the progression of infection was radically different. In contrast to the rapid plaque expansion and eventual destruction in Vero monolayers, in MDBK cells, after initial plaque formation, plaque size actually decreased and, with time, monolayers recovered. Using a green fluorescent protein (GFP)-VP16-expressing virus, we monitored infection in live individual plaques. After early stages of intense GFP-VP16 expression, expression regressed to a thin boundary at the edge of the plaques and was completely suppressed by 10 days. Cells lacking expression then began to grow into the plaque boundaries. Furthermore, following media replacement, individual cells expressing GFP-VP16 could be observed reinitiating infection. The results indicated the production of a potent inhibitory component during infection in MDBK cells, and we show the continued and prolonged presence of interferon in the medium, at times when there was no longer evidence of ongoing productive infection. We exploited the ability of V protein of simian virus 5 to degrade Stat1 and prevent interferon signaling. We established MDBK cells constitutively expressing the V protein with the resultant loss of Stat1. In comparison to the parental cells, infection in these cells now progressed at a rapid rate with expanding plaque formation. We believe the conclusions have significant implications for the study of HSV-1 and interferon signaling both in culture and in animal models.
Marie Curie Research Institute, Oxted, The Chart, Surrey RH8 0TL, United Kingdom. P.OHare@mcri.ac.uk
Cristina
C
Barreca
Peter
P
O'Hare
D000818:Animals; D002417:Cattle; D002460:Cell Line; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D017405:Herpes Simplex Virus Protein Vmw65 / Q000235:genetics / Q000378:metabolism; D018259:Herpesvirus 1, Human / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity*; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050794:STAT1 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism*; D014709:Vero Cells; D010948:Viral Plaque Assay; D014779:Virus Replication
D004268:DNA-Binding Proteins; D017405:Herpes Simplex Virus Protein Vmw65; D016898:Interferon-alpha; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D015534:Trans-Activators; D049452:Green Fluorescent Proteins