Inhibition of Endosome-Lysosome System Acidification Enhances Porcine Circovirus 2 Infection of Porcine Epithelial Cells

Increased yield of porcine circovirus-2 by a combined treatment of PK-15 cells with interferon-gamma and inhibitors of endosomal-lysosomal system acidification

“…Treatment of PK-15 cells either with IFN-g or inhibitors of endosomal-lysosomal system acidification increased the number of PCV2-infected cells ( Figs. 1 and 2), in agreement with previous studies [23,25]. Combined treatment of PK-15 cells with IFN-g and inhibitors of endosomal-lysosomal system acidification also increased the number of PCV2-infected cells.…”

“…Earlier studies have shown that the number of PCV2-infected cells can be enhanced by treatment of PK-15 cells either with interferon-gamma (IFN-g) [23] or inhibitors of endosomal-lysosomal system acidification such as ammonium chloride (NH 4 Cl), chloroquine diphosphate (CQ) and monensin [25]. In the study by Meerts et al [23], the effect of IFNg treatment of PK-15 cells on the PCV2 yield was also investigated, and it was shown that IFN-g treatment increased the yield of progeny PCV2 by 20 times.…”

“…This additional effect was possible because IFN-g and inhibitors of endoso- mal-lysosomal system acidification are known to affect different stages of PCV2 infection. Previous studies have shown that treatment of cells with IFN-g increases PCV2 infection by increasing internalization of PCV2 particles into the cell [23], while treatment of cells with inhibitors of the endosomal-lysosomal system acidification increases PCV2 infection by increasing disassembly of internalized PCV2 particles within the cell [25]. For virus yield assays, 2Â10 5 cells were seeded per well of a 24-well cell culture plate (Nunc).…”

“…Apart from PMWS, PCV2 has also been associated with various disease syndromes in pigs including porcine dermatitis and nephropathy syndrome [3,5,19,21,31,35,37], congenital tremors [6,14], reproductive failure [16,18,21,28,29,33], exudative epidermitis [38], porcine respiratory disease complex [13], proliferative and necrotizing pneumonia [11] and enteritis [4,15]. In vitro, PCV2 replicates in porcine kidney epithelial cells [2,20,25,32], and PCV2 isolation and production is routinely performed using porcine kidney (PK-15) and swine kidney (SK) epithelial cell lines [2,32]. When PCV2 replication kinetics were studied in a PK-15 epithelial cell line that was inoculated with the prototype PCV2 strain Stoon-1010 [9], 1.8% of cells were infected with a maximum yield of 3.9 log 10 TCID 50 =ml in culture supernatant [22].…”

Amino Acid Residues Critical for Endoplasmic Reticulum Export and Trafficking of Platelet-activating Factor Receptor

“…We further hypothesized that P247A is not properly trafficked, e.g. enhanced internalization, deficiency in recycling, and/or accelerated degradation, which was supported by a dramatic increase in fully glycosylated P247A in mc-PAF-exposed cells following treatment with chloroquine, a lysosomal inhibitor (28) (Fig. 6C).…”