pDCs in SIV+ RM reflect a more inflammatory rather than tolerogenic phenotype. (A) FACS plots depict gating used and the proportion of CD80+ pDCs in different tissues. FACS plots are an overlay of pDCs (black) on the HLA-DR+ LIN− population (gray). The SIV+ and SIV− animals represented here were examined at different times hence the differences in gating. The gates were placed based on CD80 expression on total lymphocytes. (B) Proportion of CD80+ pDCs or mDCs in the blood, spleen, peripheral LNs, gut LNs, and colon/rectum. *P < .01, **P < .005. ND indicates not done. (C) Intracellular cytokine expression of IFN-α and TNF-α in pDCs from the MLN and colorectum after stimulation with imiquimod or AT-2–inactivated SIVmac251. Bar chart shows the proportion of IFNα+ pDCs in the MLN or colorectum after stimulation with AT-2–inactivated SIVmac251 from 3 SIV+ RMs. (D) Relative fold expression of IDO and IL-10 mRNA in pDCs, mDCs, and CD14+ cells from individual SIV+ RMs. Fold expression was calculated using the δCt method and compared against the same gene mRNA levels in pDC from the same animal. ND indicates not done. (E) Proportion of IDO+ cells from the MLN of individual SIV+ RMs. FACS plots show pDCs, mDCs, or CD14+ cells (black) overlaid on total cells (gray background). Mean fluorescence intensity (MFI) values of IDO expression in pDCs, mDCs, or CD14+ cells are indicated on the plots.