Persistent PnV (Perina nuda virus) infection in a heterologous Lymantria xylina cell line, NTU-LY

ABSTRACT

The NTU-LY-1 cell line is a Lymantria xylina cell line; however, during cell passage, obvious cytopathic effects (CPEs) were observed under light microscopy. Round inclusion body (IB)-like particles and a few irregular larger IB-like particles were found in the cytoplasm of NTU-LY-1 cells. To further investigate the CPEs in NTU-LY-1 cells, reverse transcription–PCR screening of cytoplasmic polyhedrosis virus, infectious flacherie virus and Perina nuda virus (PnV) was performed. The results indicated that NTU-LY-1 cells were persistently infected with PnV from days 1 to 15 of culture. NTU-LY-1 cells were further subjected to Western blotting and indirect immunofluorescence assays to confirm PnV infection. Based on transmission electronic microscopy observations, the CPEs in NTU-LY-1 cells were different from those in the PnV-homologous NTU-Pn-HF cell line (a cell line of P. nuda). Membrane-bound IBs were found in newly seeded NTU-LY-1 cells. Lysed NTU-LY-1 cells formed many microsomes after 15 days of culture, and three different types of IBs could be distinguished among the microsomes, including membrane-bound, fibril-bound and sheath-bound IBs. After 15 days of culture, the cytoplasm of un-lysed NTU-LY-1 cells contained zipper-like arrays of non-membrane-bound virogenic stroma and parallel rows of viral particles that were restricted by two membranes. These viral particles were purified and showed a PnV morphology. This is the first study to show persistent PnV infection in a heterologous cell line. The findings suggest a new strategy for microbial control; moreover, the findings could support the development of a model for membrane-associated replication of positive-sense single-stranded RNA viruses.

KEYWORDS:

• Perina nuda virus
• NTU-LY cell line
• Lymantria xylina cell line
• NTU-Pn-HH cell line
• NTU-Pn-HF cell line

Acknowledgement

In memory of Prof. Chung-Hsiung Wang, who was a leadership of this article. This research was supported by the Rural Development Administration (RDA), Korea.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Rural Development Administration (RDA), Korea.