Replication of rat coronaviruses in intestinal cell line, RCN-9, derived from F344 rats

To examine the susceptibility of the epithelial cell line to rat coronavirus (RCV), we inoculated sialodacryoadenitis virus and Parker's RCV into five cell lines; JTC-19, rat L2, LLC, RCN-9 and LBC cells originating in the lungs, intestines and mammary tumors of rodents. Both RCVs were replicated in LBC and RCN-9 cells, but not in the others. The infectivity titers of both RCVs grown in RCN-9 cells were significantly higher than those in LBC cells in every passage (2.5-3.9 log rate). Both RCVs replicated in LBC cells showed higher tropism to RCN-9 cells than to LBC cells, suggesting that RCN-9 cells are more suitable for the replication of RCVs than LBC cells. The RCN-9 cell line would be useful for the investigation of RCV infection in rodents.