Figure 4.
The combined bioorthogonal pair hCXCL13-5 and hCXCL10-BCN selectively labels drug-resistant leukemic B cells over nonresistant B cells. (a) Schematic representation of receptor-controlled fluorogenic ligation of hCXCL13-5 and hCXCL10-BCN in resistant WSU-NHL cells over nonresistant Raji cells. (b) Fluorescence emission of drug-resistant B cells (CXCR3+CXCR5+) and nonresistant B cells (CXCR3–CXCR5+) after addition of hCXCL13-5 (220 nM) and hCXCL10-BCN (290 nM). Data as means ± SD (n = 3). *** for p < 0.001. (c) Representative histograms showing fluorescence activation in WSU-NHL cells. (d) Real-time imaging of chemokine ligation inside leukemic B cells (white arrows) after addition of hCXCL10-BCN (1 μM) and hCXCL13-5 (440 nM, green). Movies S3 (WSU-NHL) and S4 (Raji). Cells were costained with CellMask Deep Red (1:2000 dilution, red) as a membrane marker. Excitation wavelengths: 488 nm (hCXCL13-5), 660 nm (CellMask Deep Red). Scale bar: 10 μm.
