Chicken and duck myotubes are highly susceptible and permissive to influenza virus infection.
Bottom Line: Besides its primary function in movement and posture, skeletal muscle is a significant innate immune organ with the capacity to produce cytokines and chemokines and respond to proinflammatory cytokines.Infected chicken myotubes produced significantly higher levels of proinflammatory cytokines than did the corresponding duck cells.Our results indicate that avian skeletal muscle fibers of chicken and duck could be significant contributors to progeny production of highly pathogenic H5N1 viruses.
Affiliation: School of Veterinary Medicine and Science, University of Nottingham, Loughborough, Leicestershire, United Kingdom.Show MeSH
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Mentions: We recently reported a simple but effective method for the isolation of muscle satellite cells from several avian and mammalian species, including chicken and duck (31). Differentiated chicken and duck myotubes were infected with a LPAI H2N3 virus at a MOI of 0.1. Chicken and duck myotube cultures were spatially monitored for viral NP by immunocytochemistry at 6 h, 12 h, and 24 h p.i. (Fig. 1). At 6 h p.i., NP was detected in virtually all myotubes, but only a small proportion of myoblasts appeared to be infected. NP strongly accumulated in the nuclei and, to a lesser degree, in the sarcoplasm of infected chicken (Fig. 1A and A′) and duck (Fig. 1D to D″) myotubes. At 12 h p.i., viral NP became more intense in the sarcoplasm of chicken (Fig. 1B and B′) and duck (Fig. 1E and E′) myotubes, but infected nuclei remained strongly labeled for NP. By 24 h p.i., widespread myotube detachment from most of the culture surface had occurred. The remaining chicken (Fig. 1C and C′) and duck (Fig. 1F and F′) myotubes appeared to accumulate even more viral NP. The difference in infection patterns between myotubes and myoblasts of both avian species was also seen with the human H1N1 virus (A/USSR/77) at a MOI of 0.1 (Fig. 1G and H, respectively). Myoblasts, however, were not completely resistant to influenza virus infection; with LPAI H2N3 virus at a MOI of 1.0, both myotubes and myoblasts from chicken and duck were comparably labeled for viral NP (Fig. 1I and J, respectively). In summary, avian myotubes appeared highly susceptible to influenza virus infection.
Affiliation: School of Veterinary Medicine and Science, University of Nottingham, Loughborough, Leicestershire, United Kingdom.