A Newly Established Fin Cell Line from Tomato Hind (Cephalopholis sonnerati) and Transcriptome Profiling Characterizing Its Response to Vibrio harveyi Infection

The tomato hind (Cephalopholis sonnerati) is an emerging mariculture species increasingly threatened by Vibrio harveyi infection, yet in vitro tools for studying its immune defense remain limited. Here, we established a novel fin-derived fibroblast-like cell line, designated Tomato hind Grouper Fin (TGF), from C. sonnerati using the tissue explant method. TGF cells have been stably subcultured for more than 83 passages in Leibovitz’s L-15 medium supplemented with 20% fetal bovine serum at 28 °C. Species authentication via mt-co1 barcoding confirmed 99.9% sequence identity, and karyotype analysis revealed a diploid chromosome number of 2n = 48, matching the donor species. TGF cells exhibited robust post-thaw viability (>80%) and were amenable to exogenous nucleic acid delivery, with higher efficiency for siRNA than plasmid DNA. To evaluate immune competence, TGF cells were challenged with V. harveyi, and transcriptomic profiling was performed at 60, 90, and 120 min post-infection. A total of 1876 differentially expressed genes were identified at 120 min. KEGG enrichment analysis revealed sustained activation of Toll-like receptor, NOD-like receptor, NF-κB, TNF, and IL-17 signaling pathways across all time points. The TGF cell line represents a valuable in vitro resource for studying host–pathogen interactions of C. sonnerati.