I am currently reading a paper regarding Influenza. In the paper they describe a mutant and a WT, and the differences in replication. They grow the two strains in Vero cells (kidney epithelial cells). Why do they grow them in Vero cells, when it is a respiratory disease?
Link for article: https://pubmed.ncbi.nlm.nih.gov/9878611/
In addition to @David's answer, the viruses in this paper were specifically grown in Vero cells because of their lack of interferon expression1,2, which the authors were looking at for examining functions of the NS1 fragment from influenza.
Normally, influenza viruses are grown on MDCK cells for propagation or (more commonly) in embryonated chicken eggs. The authors propagated the viruses in eggs in this paper, as explained in the Materials and Methods. The authors also used HEK293 cells for transfection, which are used in co-culture with MDCK to generate genetically modified influenza viruses.
1: Diaz, M. O., Ziemin, S., Le Beau, M. M., Pitha, P., Smith, S. D., Chilcote, R. R., & Rowley, J. D. (1988). Homozygous deletion of the alpha- and beta 1-interferon genes in human leukemia and derived cell lines. Proceedings of the National Academy of Sciences of the United States of America, 85(14), 5259–5263. https://doi.org/10.1073/pnas.85.14.5259
2: Mosca JD, Pitha PM. Transcriptional and posttranscriptional regulation of exogenous human beta interferon gene in simian cells defective in interferon synthesis. Mol Cell Biol. 1986 Jun;6(6):2279-83. doi: 10.1128/mcb.6.6.2279-2283.1986. PMID: 3785197; PMCID: PMC367773.
@bob1 provides a specific reason for the use of Vero cells in this case, where the study concerns the behaviour of these cells in response to infection by influenza virus. However, it is worth pointing out that the implicit assumption of the poster — that one should grow a virus in the cells it infects in the wild — is questionable.
The problem has been historically that the cells a virus infects in the body cannot generally be grown in tissue culture — some kind of immortalized cell is needed. Originally — before tissue culture had been developed — viruses were passaged by inoculating eggs, and an answer I provided to another virus question goes into this area in more detail.
In summary, if you want to grow a virus to obtain large quantities of virus or its components you choose the best system available for doing that. If you want to study its pathology you inject it into a suitable animal model, or if you want to study how tissues respond to it, you choose a suitable cell line (as in this case). But the two things are generally quite different.
