Characterization of a porcine kidney cell line resistant to influenza virus infection

Derivation of chicken induced pluripotent stem cells tolerant to Newcastle disease virus-induced lysis through multiple rounds of infection

Background

Newcastle disease (ND), caused by Newcastle disease virus (NDV), is a devastating disease of poultry and wild birds. ND is prevented by rigorous biocontainment and vaccination. One potential approach to prevent spread of the virus is production of birds that show innate resistance to NDV-caused disease. Induced pluripotent stem cell (iPSC) technology allows adult cells to be reprogrammed into an embryonic stem cell-like state capable of contributing to live offspring and passing on unique traits in a number of species. Recently, iPSC approaches have been successfully applied to avian cells. If chicken induced pluripotent stem cells (ciPSCs) are genetically or epigenetically modified to resist NDV infection, it may be possible to generate ND resistant poultry. There is limited information on the potential of ciPSCs to be infected by NDV, or the capacity of these cells to become resistant to infection. The aim of the present work was to assess the characteristics of the interaction between NDV and ciPSCs, and to develop a selection method that would increase tolerance of these cells to NDV-induced cellular damage.

Results

Results showed that ciPSCs were permissive to infection with NDV, and susceptible to virus-mediated cell death. Since ciPSCs that survived infection demonstrated the ability to recover quickly, we devised a system to select surviving cells through multiple infection rounds with NDV. ciPSCs that sustained 9 consecutive infections had a statistically significant increase in survival (up to 36 times) compared to never-infected ciPSCs upon NDV infection (tolerant cells). Increased survival was not caused by a loss of permissiveness to NDV replication. RNA sequencing followed by enrichment pathway analysis showed that numerous metabolic pathways where differentially regulated between tolerant and never-infected ciPSCs.

Conclusions

Results demonstrate that ciPSCs are permissive to NDV infection and become increasingly tolerant to NDV under selective pressure, indicating that this system could be applied to study mechanisms of cellular tolerance to NDV.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0659-3) contains supplementary material, which is available to authorized users.

A variant of MDCK cell line which restricted growth of influenza viruses mainly through suppression of viral primary transcription

By serial subculture of MDCK cells which survived high multiplicity infections with AWBY-140, a weakly cytolytic mutant of influenza virus A/WSN (H1N1), we established a variant cell line (MDCK-L cells) that was uniquely resistant to infection with influenza A and B viruses, yielding 3 to 4 orders lower amount of progeny virus compared with MDCK cells. Competitive polymerase chain reaction revealed that the amount of primary transcript produced in MDCK-L cells infected with 10 PFU/cell of influenza virus A/Aichi was suppressed to 1/100 of that in MDCK cells similarly infected, although the amount of virus adsorbed to MDCK-L cells was 1/4 of MDCK cells. Even when MDCLK-L cells were infected with 40 PFU/cell of Aichi to overcome the lower amount of internalized virus in those cells, the results were the same. The synthesis of v-, c- and mRNAs, as well as proteins of infected A/Aichi was below detectable level in MDCK-L cells, in contrast with MDCK cells, where they were clearly demonstrable by ribonuclease protection assay or polyacrylamide gel electrophoresis.

Isolation and characterization of a novel mutant mouse cell line resistant to Newcastle disease virus: constitutive interferon production and enhanced interferon sensitivity

In our attempt to isolate mutant cell lines resistant to Newcastle disease virus (NDV) we developed an improved procedure for enrichment of NDV-resistant cells from mouse FM3A cells and isolated a novel NDV-resistant mutant cell line, Had-2, with characteristics different from Had-1, a previously reported NDV-receptor-deficient mutant strain. Had-2 cells adsorbed NDV normally but the accumulation of viral mRNAs and proteins was inhibited. Had-2 cells had to be grown at higher cell densities in order to be NDV-resistant, and it was revealed that they did not exhibit NDV-resistance when grown at lower cell densities. A conditioned medium prepared from a culture of Had-2 cells grown at high cell density was able to make a low-density culture NDV-resistant. The activity of the conditioned medium to induce NDV-resistance was completely neutralized by addition of both anti interferon (IFN)-alpha and anti IFN-beta antibodies, indicating that Had-2 cells were constitutively releasing IFNs, though their levels were rather low. Had-2 cells were also characterized by an increased sensitivity to IFNs as compared with the parental FM3A cells, since the conditioned medium containing IFNs did not render FM3A cells resistant to NDV.

Structural determination of gangliosides that bind to influenza A, B, and C viruses by an improved binding assay: strain-specific receptor epitopes in sialo-sugar chains

An improved binding assay for detection of ganglioside receptors for influenza A, B, and C viruses was developed. In this system, the virions bound to gangliosides that were developed on a silica gel thin-layer plate were detected by mouse monoclonal antibody against viral hemagglutinin and peroxidase-conjugated anti-mouse immunoglobin. No hydrolysis of the gangliosides by viral receptor-destroying enzyme was detected in the present condition. The reactivity of the viruses to gangliosides depended on the amount of developed gangliosides (10 pmols-10 nmols), the molecular species of sialic acid, and their sugar sequences. Human influenza A (PR/8/34), B (Lee/40), and C (Ann Arbor/1/50) viruses bound different receptor epitopes of sialo-sugar chains of gangliosides. The A/PR/8 virus bound most effectively to Neu5Ac-containing lacto-series gangliosides carrying type I and type II sugar chains, followed by ganglio-series and hematoside-series gangliosides. The A/PR/8 virus weakly bound to Neu5Ac alpha 2,6lactotetraosylceramide [IV6(Neu5Ac)Lc4Cer] and Neu5Ac alpha 2,6paragloboside [IV6(Neu5Ac)nLc4Cer] carrying Neu5Ac alpha 2,6Gal sequence, although their Neu5Ac alpha 2,3Gal derivatives were the most potent gangliosides tested. B/Lee/40 bound restrictively to IV6(Neu5Ac)Lc4Cer and IV6(Neu5Ac)nLc4Cer, which carry Neu5Ac alpha 2,6Gal sequence, and type I and type II lacto-series sugar chain, respectively. C/Ann Arbor/1/50 reacted only with 9-O-Ac-Neu5Ac-carrying sugar chains in all the gangliosides tested. This method also allowed the microanalysis of receptor gangliosides of unknown samples. ESK cells, sensitive to the influenza A viruses infection, expressed several kinds of receptor active gangliosides, while those from ESK-R cells, resistant to the virus infection, were undetectable.