Establishment and characterization of SSI cell line from Sebastes schlegelii intestine for investigating the immune response to Pathogenic Bacteria.

As a commercially valuable fish species, Sebastes schlegelii faces threats from pathogenic bacteria like Edwardsiella piscicida during aquaculture. The global host range of E. piscicida encompasses various species, yet its pathogenic mechanism remains incompletely elucidated. Cell lines offer invaluable in vitro resources for studying the pathogen pathogenicity. Here, we established and characterized a cell line derived from the intestinal tissue of the S. schlegelii, designated as SSI. SSI has undergone continuous subculturing for over 80 passages, demonstrating robust growth in DMEM supplemented with 10%-20% FBS and 20 μM HEPES at 24°C. Karyotype analysis and 18S rRNA amplification confirm its origin. SSI exhibits high transfection efficiency for exogenous DNA, making it suitable for gene expression and intestinal function analysis. E. piscicida infects SSI cells at low densities without inducing morphological changes within 6 h of infection, suggesting the potential of SSI as an in vitro model for studying E. piscicida pathogenicity. This cell line provides a valuable tool for investigating mucosal immunity and E. piscicida pathogenic mechanisms in marine fish.