Lastly, having observed the marked induction of IFN-γ/TNF-α co-producing CD4+ T cells following PCV2 vaccination and also PCV2 infection, we compared the CD27 expression in PCV2-specific IFN-γ+TNF-α+CD4+ T cells from VA animals at 24 dpv (day of experimental infection), IN animals at the day of euthanasia and VI animals at both time points (Figure 6). This evidence concerns the gene CD4 and infection.