Figure 3.

ZXL1 competed with mannose receptor (MR) for binding to mannose-capped lipoarabinomannan (ManLAM) or Mycobacterium tuberculosis (M. tb) H37Rv. ManLAM (10 µg/ml in phosphate-buffered saline) or heat-inactivated M. tb H37Rv (1 × 10⁶ colony forming units (CFUs)/ml) was coated on an enzyme-linked immunosorbent assay plate, and 2 µmol/l of biotin-labeled ZXL1 and competitors were added and incubated. In the background control, the ManLAM (or heat-inactivated M. tb H37Rv) was coated on the wells, but none of the single-stranded DNA aptamers were added. For each sample, the optical density at 450 nm (OD₄₅₀) of the background control was subtracted from the OD₄₅₀ of the experimental sample. (a) Human MRp1 and MRp2 inhibited binding of ZXL1 to M. tb H37Rv. Percentage binding: OD₄₅₀ value of 0.5, 2.5, 12.5, or 25 µmol/l competitor group/OD₄₅₀ value of 0 µmol/l competitor group. *P < 0.05 versus 0 µmol/l competitor group. All data are shown as the means ± SEMs (n = 3). (b) Human MRp1 and MRp2 inhibited binding of ZXL1 to ManLAM/M. tb H37Rv. Percentage binding: OD₄₅₀ value of 15, 30, or 50 µmol/l human MRp1 (or MRp2) group/OD₄₅₀ value of 0 µmol/l human MRp1 (or MRp2) group; *P < 0.05, **P < 0.01 versus 0 µmol/l human MRp1 (or MRp2) group. All data are shown as the means ± SEMs (n = 3). (c) Soluble ManLAM inhibited binding of ZXL1 to ManLAM coated on the well. Percentage binding: OD₄₅₀ value of ManLAM competitor group/OD₄₅₀ value of 0 µmol/l ManLAM competitor group. All data are shown as the means ± SEMs (n = 3). (d) Mannan and N-acetyl-D(+)-glucosamine inhibited binding of ZXL1 to ManLAM. Percentage binding: OD₄₅₀ value of 2.5, 25, or 250 µmol/l carbohydrate competitor group/OD₄₅₀ value of 0 µmol/l carbohydrate competitor group. *P < 0.05 versus 0 µmol/l carbohydrate competitor group. All data are shown as the means ± SEMs (n = 3).