Interactions of poult enteritis and mortality syndrome-associated reovirus with various cell types in vitro.

An avian reovirus, ARV-CU98, has recently been isolated from poults experiencing poult enteritis and mortality syndrome (PEMS). To further understand ARV-CU98 and its role in PEMS, the current study investigates interactions of ARV-CU98 with various cell types in vitro. When macrophages, B cells, T cells, and liver cells of chicken or turkey origin were co-incubated with ARV-CU98, only cells of liver origin demonstrated cytopathic effects, the presence of viral antigen, and reduced metabolic activity over time. Furthermore, distinctive pockets of viral particles were evident in electron microscopic examination of a chicken hepatocellular carcinoma (LMH) cell line, but not in a chicken macrophage cell line (MQ-NCSU) co-incubated with virus. Additional evidence of viral replication in LMH, cells but not MQ-NCSU cells was demonstrated by the presence of two viral bands (43 and 145 kD size) in cell lysates from LMH cells exposed to ARV-CU98. Although not capable of being infected by ARV-CU98, MQ-NCSU cells do appear to be activated by the virus since IL-1 mRNA expression is increased in MQ-NCSU cells 2 h after addition of the virus. LMH cells exposed to the virus demonstrate a decrease in IL-1 mRNA expression by 8 to 10 h after addition of the virus, perhaps corresponding to the initiation of infection by the virus. In conclusion, this study demonstrates that ARV-CU98 actively infects and replicates in LMH cells, but not in lymphocytes or macrophages, suggesting that the liver may be a target and site of replication of ARV-CU98 in poults experiencing PEMS.