THE FAS/FASL PATHWAY MEDIATES APOPTOSIS OF SPLENIC LYMPHOCYTES IN PIGLETS INFECTED WITH PCV2

Abstract

The aim of this study is to investigate the molecular pathogenetic mechanism of PCV2-induced apoptosis in the porcine spleen. Nineteen piglets were allotted into four groups and sacrificed at 0, 14, 21, or 35 days post inoculation (DPI) with PCV2. PCV2 infection was found to be associated with apoptosis of porcine spleen by flow cytometry, as caspase-3 activity in the spleens of the three experimental groups (14, 21, and 35 DPI) was significantly higher than in the control group (0 DPI) (p<0.01). Expression of the FasL mRNA was upregulated by PCV2 infection, particularly at 21 and 35 DPI. Caspase-8 and caspase-9 activity increased in PCV2 infection was also detected. The concentration of sFas in the serum was decreased at 14 DPI compared to the control group (p<0.05). The data presented here in support the hypothesis that PCV2 induces apoptosis of lymphocytes in the spleens of infected piglets, and that induction of apoptosis is mediated, at least partially, through the Fas/FasL pathway.