Figure 3. Chronic infection induces CD200 and CD200R expression in CD4 T cells.

C57BL/6 (A–E) and 4-get (F) mice were infected with S. mansoni; MesLN (A–D, F) and spleen (E) were analyzed. A. Representative contour plot of CD44 with CD200, and B. CD44 with CD200R is shown for gated CD4 T cells. Upon infection (8 wk), CD44^hiCD200⁺CD4 cells (panel A, R3) increased from 7.71±2.66% (n = 14) to 15.2±3.72% (n = 17, p<0.0001); CD44^hiCD200R⁺CD4 cells (panel B, R3) increased from 4.36±1.69% (n = 14) to 15.3±4.67% (n = 17, p<0.0001). Data were pooled from 4 independent experiments. C. Dot plots show CD200 and CD200R co-expression in CD44^lo and CD44^hi CD4 cells from uninfected and infected mice. D. Graph shows absolute numbers of CD200R⁺ (panel B, R3) and CD200R^– (panel B, R2) CD44^hiCD4 cells from 4 independent experiments. Upon infection CD44hiCD200R+ cells increased from (2.7±0.6)× 10⁵ (n = 14) to (10.8±3.2)×10⁵ (n = 17, ***p = 3.03×10^–10), while CD44^hi CD200R^– cells increased from (7.9±3.3)×10⁵ to (18.6±11.9)×10⁵ (**p = 0.003). E. Contour plots show CD200R expression in proliferating (BrdU⁺) cells, in gated CD4 cells for spleen of uninfected and infected mice. Upon infection BrdU⁺CD200R⁺ CD4 T cells increased from 4.5±0.69 (n = 4) to 46.6±17 (n = 10) p<0.0005. Specificity controls for BrdU staining are shown in Figure S7A & B. F. Contour plots (left) show CD200 and eGFP expression; CD200⁺GFP⁺CD4 cells increased from 0.64±0.12% to 13.7±7.24% after infection (p = 0.01, n = 4). Histogram overlays (right) show CD200 and CD200R levels in gated GFP⁺ (green line) and GFP^– (filled histograms) CD4 cells from infected mice. Control stainings for intracellular GFP staining are shown in Fig S5B & C. ** = p<0.0001, * = p<0.001. Results are representative of at least 4 (A–D) and 3 (E-F) independent experiments (n = 3 mice/group).