Figure 8. Tfh cells respond to antigenic re-stimulation signals.
(A) Schematic diagram of Tfh (PD-1hiBlimp1YFP−) and Th1 (PD-1intBlimp1YFP+) SM cells sorted from day 8 LCMV infected mice. (B) Representative overlaid histograms for CXCR5 expression and cell size of Th1 (blue) and Tfh (red) cells. (C) Overlaid histograms show proliferations of Th1 (left) and Tfh (right) cells in the absence of stimulation (gray filled) or in the presence of 8 μg/ml of αCD3 mAbs with different amount of αCD28 mAbs (8 μg/ml in black; 2 μg/ml in blue, 0.5 μg/ml in red) (upper panels). Quantifications made as percentages of divided cells by Tfh (black) and Th1 (gray) cells 3 days after in vitro culture (lower panel). (D) Cell sizes determined by FSC of activated Tfh (red) and Th1 (blue) cells compared to those of non-activated Tfh (black) and Th1 (gray filled) cells. Quantitation made as MFIs of FSC. (E) Level of Blimp1YFP expression depicted by overlaid histograms of activated Tfh (red) and Th1 (blue) cells compared to those of non-activated Tfh (black) and Th1 (gray filled) cells. Dashed lines show background level of Blimp1YFP by CD44lo naïve CD4 T cells in naïve mouse. (F) Quantitation made as percentages of Blimp1YFP-expressing cells in indicated culture conditions. Data are representative of two or more independent experiments using 3–5 replicate wells per group. (G–H) OTII CD4 (CD45.1+) T cells were transduced with a retroviral vector that expresses Blimp1 with GFP. (G) Blimp1int (GFPint) and Blimp1hi (GFPhi) expressing cells were sorted based on GFP expression (left), and transferred into B6 (CD45.2+) mice. (H) Expansion of OTII CD4 T cells were measured 8 days after NP-OVA immunization, as % of total CD4 T cells. n = 3–4 per group. ** P < 0.01, *** P < 0.001. Shown as mean and SEM.