FIG 3.

CpClec-Fc interacts with sulfated proteoglycans on intestinal epithelial cells. (A) Fixed HCT-8 cells were incubated with CpClec-Fc or Fc alone in the presence of GAGs or fucoidan. (B) HCT-8 cells were treated with heparinase II or lyase buffer, fixed, and incubated with CpClec-Fc or Fc alone. (C) HCT-8 cells were incubated with α-xyloside, β-xyloside, or medium alone; fixed; and incubated with CpClec-Fc or Fc alone. (D) HCT-8 cells were incubated with NaCl, NaClO₃, or medium alone; fixed; and incubated with CpClec-Fc or Fc alone. (A to D) Binding was quantified by ELISA. (E and F) Fixed CHO K1, pgsA-745, and pgsD-677 cells were incubated with CpClec-Fc or Fc alone. Binding was quantified by ELISA (E) or visualized by fluorescence microscopy (F). Scale bars = 100 μm. For all quantification experiments, binding of CpClec-Fc was normalized to the binding of Fc alone. Quantification data represent the mean ± the SEM. **, P < 0.05; ***, P < 0.0005 (compared to binding in the control [buffer or medium alone or CHO K1 cells]).