In vitro infection of cells of the monocytic/macrophage lineage with bovine leukaemia virus.
The oncogenic retrovirus bovine leukaemia virus (BLV) primarily infects B cells. Most infected animals remain asymptomatic for long periods of time before an increase in circulating B cells or localized tumours can be observed. This long clinical latency period may be explained by cells of the monocyte/macrophage lineage (M/M) becoming infected and acting as a reservoir for the virus, as shown for other retroviruses (human immunodeficiency virus-1, feline immunodeficiency virus). M/M cells in different stages of differentiation (HL-60, THP-1, U-937, J774, BGM, PM2, primary macrophages of sheep and cows) were cultured with BLV produced by permanently infected donor cells (FLKBLV and BLV-bat(2)). Donor cells were inhibited from multiplying by either irradiation or treatment with mitomycin C. In other experiments, supernatant from donor cells containing virus was used. In co-culture with the donor cells, the less differentiated monocytic cells showed severe cellular changes such as differentiation, vacuolization, cell lysis and membrane blebbing; apoptosis was a frequent phenomenon. Budding and extracellular viruses were also observed. The more differentiated macrophage cells, although they showed less signs of infection by microscopy, had a complete BLV protein profile, as seen by Western blotting; bands corresponding to p24CA (Gag) and its precursors were clearly seen. In addition, gp51SU was identified by syncytia formation assays. It is concluded that M/M cells may be infected by BLV, the consequences of the infection differing according to the type of cell.
Doménech
A
A
Dpto Patología Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain.
Goyache
J
J
Llames
L
L
Jesús Payá
M
M
Suárez
G
G
Gómez-Lucía
E
E
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002417:Cattle; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D018920:Coculture Techniques; D003588:Cytopathogenic Effect, Viral; D015683:Gene Products, gag / Q000096:biosynthesis; D015726:Giant Cells / Q000502:physiology; D001909:Leukemia Virus, Bovine / Q000502:physiology* / Q000648:ultrastructure; D008264:Macrophages / Q000648:ultrastructure / Q000821:virology*; D008854:Microscopy, Electron; D009000:Monocytes / Q000648:ultrastructure / Q000821:virology*; D012756:Sheep; D014759:Viral Envelope Proteins / Q000096:biosynthesis; D014771:Virion / Q000502:physiology
D015683:Gene Products, gag; D014759:Viral Envelope Proteins