A New Cell Line from the Brain of Red Hybrid Tilapia (Oreochromis spp.) for Tilapia Lake Virus Propagation.

Tilapia lake virus (TiLV) presents a substantial threat to global tilapia production. Despite the development of numerous cell lines for TiLV isolation and propagation, none have been specifically derived from red hybrid tilapia (Oreochromis spp.). In this study, we successfully established a new cell line, RHTiB, from the red hybrid tilapia brain. RHTiB cells were cultured for 1.5 years through over 50 passages and demonstrated optimal growth at 25 °C in Leibovitz-15 medium supplemented with 10% fetal bovine serum at pH 7.4. Morphologically, RHTiB cells displayed a fibroblast-like appearance, and cytochrome oxidase I gene sequencing confirmed their origin from Oreochromis spp. Mycoplasma contamination testing yielded negative results. The revival rate of the cells post-cryopreservation was observed to be between 75 and 80% after 30 days. Chromosomal analysis at the 25th passage revealed a diploid count of 22 pairs (2n = 44). While no visible cytopathic effects were observed, both immunofluorescence microscopy and RT-qPCR analysis demonstrated successful TiLV propagation in the RHTiB cell line, with a maximum TiLV concentration of 107.82 ± 0.22 viral copies/400 ng cDNA after 9 days of incubation. The establishment of this species-specific cell line represents a valuable advancement in the diagnostic and isolation tools for viral diseases potentially impacting red hybrid tilapia.

Mutations in NLRP7 are associated with diploid biparental hydatidiform moles, but not androgenetic complete moles.

BACKGROUND: NLRP7 (NALP7) has been identified as the major gene involved in the inherited predisposition to recurrent molar pregnancies, a rare recessive condition in which affected individuals have complete hydatidiform moles of diploid biparental origin (BiCHM). The role of NLRP7 in other types of molar pregnancy and reproductive wastage has not been conclusively demonstrated. The purpose of this study was to clarify this by identifying NLRP7 variation in two clinically well-defined groups of patients: women with recurrent BiCHM, and women with three or more recurrent complete hydatidiform moles of proven androgenetic origin (AnCHM). METHODS: Fluorescent microsatellite genotyping of molar tissue was used to establish a diagnosis of recurrent BiCHM (four novel cases) or recurrent AnCHM (nine women with multiple CHM). These two groups were subsequently screened for mutations in NLRP7 using DNA sequencing. Additional screening for non-pathological variants was performed in 21 previously published cases of recurrent BiCHM. Taqman genotyping was used to determine the frequency of novel NLRP7 variants in two control cohorts of Caucasian and Asian women with no adverse reproductive outcomes. RESULTS: Of the four novel cases with recurrent BiCHM, two were homozygous for mutations in NLRP7 while one was a compound heterozygote for a nonsense mutation and a pathological variant. No NLRP7 mutations or pathological variants were identified in the fourth case. None of the women with AnCHM carried any mutations or pathological variants of NLRP7. A single case of AnCHM was found to be heterozygous for a novel variant (R413Q). CONCLUSION: NLRP7 mutations do not represent a major cause of AnCHM.

Antiviral Activity of Ribavirin against Tilapia tilapinevirus in Fish Cells.

The outbreak of the novel Tilapia tilapinevirus or Tilapia lake virus (TiLV) is having a severe economic impact on global tilapia aquaculture. Effective treatments and vaccines for TiLV are lacking. In this study, we demonstrated the antiviral activity of ribavirin against TiLV in E-11 cells. Our findings revealed that at concentrations above 100 µg/mL, ribavirin efficiently attenuates the cytopathic effect of the TiLV infection in fish cells. When administered in a dose-dependent manner, ribavirin significantly improved cell survival compared to the untreated control cells. Further investigation revealed that the cells exposed to ribavirin and TiLV had a lower viral load (p < 0.05) than the untreated cells. However, at concentrations above 1000 µg/mL, ribavirin led to cell toxicity. Taken together, our results demonstrate the efficacy of this antiviral drug against TiLV and could be a useful tool for future research on the pathogenesis and replication mechanism of TiLV as well as other piscine viruses.