FIGURE 6.

Heterologous vaccine immunogenicity—IFN-γ production of CD4, CD8, and TCR-γδ T cells. (A) Gating hierarchy to assess the heterologous IFN-γ response of T-cell subsets to the respective PRRSV type-2 challenge strains. The gating hierarchy follows largely the proliferation analysis shown in Figure 5. However, instead of gating on proliferating cells, IFN-γ was analyzed in a FSC-A/IFN-γ plot. The IFN-γ gate was set using the appropriate FMO control (top right plot). Panels (B–D) show the IFN-γ responses of CD4 (B), CD8 (C), and TCR-γδ T cells (D) according to their challenge groups—MOCK (gray), 1-4-4 (NADC30, dark blue), NC174 (red), VR2332 (green), and 1-4-2 (NADC20, light blue). The black bars represent the median values; in addition, individual data points are shown for MOCK vaccinated animals (open diamonds) and MLV vaccinated animals (filled squares). Data were statistically analyzed using a 2-way ANOVA with time and vaccination as the two parameters and Tukey’s multiple comparison test. ^****p < 0.0001, ^***p < 0.001, ^**p < 0.01, *p < 0.05.