Expanding the Fish‐Brain Invitrome With the Senegalese Sole <scp>SsB</scp> ‐1 Cell Line—A Versatile Model for Neurotropic Virus Research

Cell lines are essential tools for studying animal physiology and immunopathology, reducing the use of live animals and supporting the 3Rs principle of reduction, refinement, and replacement. The Senegalese sole (Solea senegalensis), a relevant species for Spanish aquaculture diversification, lacks established in vitro models. We developed SsB-1, the first brain-derived cell line from this species, providing a valuable platform for studying virus-host interactions. SsB-1 exhibits glial features, stable morphology, and high susceptibility to several betanodavirus (NNV) genotypes, enabling detailed analysis of neurotropism and virulence mechanisms. Its selective permissiveness to NNV and limited replication of infectious pancreatic necrosis virus (IPNV), spring viremia of carp (SVCV), and rhabdovirus eel virus European X (EVEX) highlight its versatility. The ability of some viruses to enter cells without triggering cytopathic or antiviral responses also points to new research avenues for potential reservoir roles in flatfish. Overall, SsB-1 offers a robust, ethical, and versatile model to advance virological and immunological research in support of sustainable marine aquaculture.