Mosquito cells (C6/36) fail to support the complete replication of Penaeus merguiensis hepandensovirus

- Hepandensoviruses (HDVs) are serious pathogens in shrimp aquaculture.
- C6/36 cell culture is reported to grow Penaeus monodon hepandensovirus.
- Our study considers if Penaeus merguiensis (PmeHDV) can also be grown in C6/36.
- Copies of PmeHDV measured by qPCR dropped from ∼105 to 102 with serial passage.
- C6/36 allows the early stages of PmeHDV replication without viral patency.

Mosquito cell lines (C6/36) were reported in the literature to support the propagation of Penaeus monodon hepandensovirus (PmoHDV). We aim to evaluate the susceptibility and viral propagation of P. merguiensis hepandensovirus (PmeHDV) which is ∼22% different to PmoHDV in Aedes albopictus cell line (C6/36). Cellular changes in the infected cell culture were detected. Vacuole formation was seen in both infected and uninfected cell cultures. The average number of disrupted cellular membranes in the infected cells (presumptive dead cells) was significantly higher than that of uninfected cells at passage two (F = 9.749, d.f. 1, 22, p < 0.05). Using a proliferation assay, light absorption of infected cells peaked at 2 weeks post-infection (O.D. = 0.27) but was significantly lower than that of the uninfected groups (O.D. = 0.37) (F = 6.879, d.f. 1, 94, p < 0.05) suggesting hindered cell growth. PCR of the serial passages of the infected cell cultures indicated weak positive results for PmeHDV infection and TaqMan quantitative PCR confirmed that the average number of viral copies declined from 3.8 × 105 to 5.69 × 102 copies per μL and the mean of cycle times increased from 19.26 to 27.63. These results are interpreted to mean C6/36 allows the initial stage of PmeHDV replication, but the virus was incapable of using C6/36 for patent replication of its' virions.

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