Establishment and characterization of fin-derived cell line from ornamental carp, Cyprinus carpio koi, for virus isolation in India.

Cyprinus carpio koi fin (CCKF) cell line was established and characterized from the caudal fin tissue of ornamental common carp, C. carpio koi. This cell line has been maintained in L-15 medium supplemented with 15% foetal bovine serum (FBS) and subcultured more than 52 times over a period of 24 mo. The CCKF cell line consisted of epithelial cells and was able to grow at temperatures between 22 and 35°C with an optimum temperature of 28°C. The growth rate of these cells increased as the proportion of FBS increased from 2 to 20% with optimum growth at the concentrations of 15% FBS. Karyotype analysis revealed that the modal chromosome number of CCKF cells was 2n = 100. Partial amplification and sequencing of fragments of two mitochondrial genes 16S rRNA and COI confirmed that CCKF cell line originated from ornamental common carp. The CCKF cells showed strong reaction to the cytokeratin marker, indicating that it was epithelial in nature. The extracellular products of Vibrio cholerae MTCC 3904 and Aeromonas hydrophila were toxic to the CCKF cells and not susceptible to viral nervous necrosis virus (VNNV). These CCKF cells were confirmed for the absence of Mycoplasma sp. by polymerase chain reaction. Furthermore, 90% of viable cells could be effectively revived 4 mo after cryopreservation from CCKF cell population suggesting the possibility of long-term storage of the cells.