Analysis of FoxP3+cells in SIV and PCV2 infection. (A) Cell suspensions isolated from the blood of GF piglets infected with SIV or PCV2 (different animal groups depicted on x-axes) were analyzed by flow cytometry for the proportion of FoxP3+CD25— and FoxP3+CD25+ cells (depicted above each graph) among gated CD4+ αβ T cells. Note that analysis of control GF piglets or GF piglets infected with PRRSV did not differ from SIV animals and therefore these are not shown. Each dot in the graphs represents an individual animal and the mean for all animals in the same group is indicated by a horizontal line. Groups of animals that show a statistically significant difference (p < 0.0001) from GF animals are light-grey boxed. (B) Representative detailed analysis of FoxP3 and CD25 expression by gated CD4+CD8α— (R1) and CD4+CD8α+ (R2) αβ T cells in the blood of PCV2 infected GF piglets.