Productive infection of continuous lines of channel catfish leukocytes by channel catfish virus

Channel catfish virus (CCV) undergoes extensive replication in fingerling catfish and establishes latent infection in survivors. Although the site of viral latency in carriers is unknown, a variety of tissues, including leukocytes, have been implicated. To explore the interaction of CCV and leukocytes further, we examined in vitro infection of continuous lines of cloned catfish B cells and non-cloned lines containing predominantly macrophages and putative T-cells. Our results indicate that all three leukocyte subpopulations were productively infected with CCV, but that the kinetics of infection and the final yields differed markedly. These findings shed light on CCV-leukocyte interaction and suggest that CCV-infected autologous macrophage or T-cell lines might be suitable targets for assays of catfish cytotoxic T cell activity.