Figure 4

Co-localization of GAGs [CS, decorin (DS)] and PCV2 particles on T-lymphoblasts of Landrace and Piétrain pigs. Cells were incubated with PCV2 particles for 1 h at 4℃. A double IF staining was performed to detect GAGs and PCV2 capsid proteins. GAGs were stained in green, and the PCV2 virions were stained in red. Cell nuclei were co-stained in blue. All data were obtained from three pigs of each breed for T-lymphoblasts. Within each replicate, the mean was calculated based on ten randomly selected fields. Visualization of co-localization was performed by confocal microscopy. A Representative confocal images of cells with 1121 and DE222-13 particles colocalized with GAG. Co-localization between CS/decorin (DS) and PCV2 within PCV2⁺ T-lymphoblasts was indicated by white arrows. B, C Co-localization assays between PCV2 particles and CS/decorin (DS). Specifically, the percentage of PCV2⁺ cells was examined (a); fluorescing area of bound PCV2 particles per PCV2⁺ cell was quantitated using ImageJ in pixels (b); the percentage of cells displaying co-localization between PCV2 particles and GAG was assessed (c); for each PCV2-GAG colocalized cell, the proportion of PCV2⁺ pixels that are also GAG expression was determined based on individual fluorescent pixels per cell (d). Data are represented as means ± SD from three replicates.