Establishment and characterisation of the first cell line from the giant Amazonian fish Arapaima gigas and its susceptibility to Tilapia Lake virus (TiLV).

This study aimed to establish and characterise a cell line derived from the caudal fin of Arapaima gigas for biotechnology and virology applications. Primary cell cultures were established using the explant technique, and key parameters, including growth performance, cryopreservation capacity, and viral susceptibility, were evaluated. The resulting line, designated AgFn, was successfully propagated through 25 passages during the experimental period, exhibiting a predominant fibroblast-like morphology from passage 10 onwards. Optimal cell proliferation was observed at an incubation temperature of 32 °C with the addition of 20% fetal bovine serum (FBS). Cryopreservation at - 80 °C resulted in cell viability of approximately 80% after one week and 65% after one year of storage. Infection assays with Tilapia Lake virus (TiLV) showed no cytopathic effects, and RT-PCR analysis detected no TiLV-specific amplification products, indicating that AgFn cells did not support detectable TiLV infection under the conditions evaluated. This work represents a significant step toward the development of in vitro models for Amazonian fish species, with potential applications in virology, toxicology, and conservation research.