Bovine herpesvirus 1-induced apoptosis occurs at the G0/G1 phase of the cell cycle.
We have previously shown that bovine herpesvirus 1 (BHV-1), even when inactivated, induces apoptotic cell death in mitogen-stimulated bovine peripheral blood mononuclear cells (PBMCs) (Hanon et al., 1996, J. Virol. 70, 4116-4120). In order to gain insight into this process, we have investigated the cell cycle phase at which BHV-1 induces apoptosis in PBMCs. Our results show that the percentage of cells that progress through the S phase was always lower in BHV-1-infected PBMCs than in control cells. This effect was not due to a defective activation of mitogen-stimulated PBMCs since BHV-1 only slightly affected the percentage of cells expressing BoCD25, a well-known lymphocyte activation marker. Furthermore, mimosine and cyclosporine A, two chemicals that inhibit entry into the S phase of the cell cycle by different pathways, did not affect the ability of BHV-1 to induce apoptosis. BHV-1-induced apoptosis also occurred in unstimulated PBMCs and interestingly, this was associated with the expression of c-myc and BoCD25 proteins both of which are related to cell cycle progression. All together, these data provide evidence demonstrating that BHV-1-induced apoptosis occurs at the G0/G1 phase of the cell cycle.
Hanon
E
E
Department of Immunology/Vaccinology, Faculty of Veterinary Medicine, University of Liège, Belgium. hanon@stat.fmv.ulg.ac.be
Hoornaert
S
S
Dequiedt
F
F
Vanderplasschen
A
A
Lyaku
J
J
Willems
L
L
Pastoret
P P
PP
D000818:Animals; D017209:Apoptosis; D002417:Cattle; D002460:Cell Line; D016193:G1 Phase; D007242:Herpesvirus 1, Bovine / Q000502:physiology*; D007963:Leukocytes, Mononuclear / Q000166:cytology* / Q000821:virology; D008934:Mitogens / Q000494:pharmacology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D016192:Resting Phase, Cell Cycle
D008934:Mitogens; D015240:Phorbol 12,13-Dibutyrate