Detection and analysis of bovine foamy virus infection by an indicator cell line

Aim:To determine the infectivity and replication strategy of bovine foamy virus(BFV) in different cultured cells using the BFV indicator cell line (BICL) system.Methods:BFV infection was induced by the co-culture method or the transienttransfection of the infectious BFV plasmid [pCMV (cytomegalovirus)-BFV] clone.The infectivity of BFV was monitored by the percentage of green fluorescentprotein-positive cells in the BICL.The effect of reverse transcriptase inhibitorzidovudine (AZT) on BFV replication was also evaluated in the BICL.Results:The titer of BFV in fetal bovine lung cells was 4-5-folds more than that in either293T or HeLa (Cells from Henrietta lacks) cells using the co-culture method,and inthe meantime was significantly higher than that produced by the infectious clonepCMV-BFV in the same cells.AZT had only a minor effect on viral titers whenadded to cells prior to the virus infection.In contrast,viral titers reduced sharplyto the level of the negative control when the virus was produced from cells in thepresence of AZT.Conclusions:BICL can be used for the titration of the BFV viralinfection in non-cytopathic condition.In addition,we proyide important evi-dence to show that reverse transcription is essential for BFV replication at a latestep of viral infection.