Figure 4

Frequency of PCV2-ORF2-specific cytokine-producing CD4 ⁺ T cells. A) Porcine PBMCs were stimulated with PCV2-ORF2 over night or were cultured in medium as negative control. CD4⁺ T cells were gated and analysed for production of IFN-γ and TNF-α by intracellular cytokine staining (top panel). Cytokine-producing CD4⁺ T cell subsets were further sub-gated for the analysis of CD8α and CD27 expression (bottom panel). Red dots indicate cytokine-producing CD4⁺ T cells; grey dots represent total CD4⁺ T cells. FCM data is shown for one representative animal of the control (CO) and vaccinated group (VA) at 24 dpv. B) Stacked bar charts indicate percentages of cytokine-producing CD4⁺ T cells within total CD4⁺ T cells from individual animals of the treatment groups (CO = control, VA = vaccinated, IN = infected, VI = vaccinated & infected) prior to infection (24 dpv) and at the end of the study (56 dpv). Hatched bars represent percentages of IFN-γ single-producing CD4⁺ T cells and filled bars illustrate percentages of IFN-γ/TNF-α co-producing CD4⁺ T cells within total CD4⁺ T cells.