Figure 4

Fluorochrome-conjugated nanobodies JK2 and JK36 detect CD38 on the surface of human lymphoma cell lines saturated with daratumumab. LP-1 myeloma cells were preincubated with a saturating dose of DarzalexR, (daratumumab, human IgG1) (grey histograms) or with PBS (open histograms) before addition of fluorochrome-conjugated CD38-specific mAb LS198-4-3 or monovalent nanobodies WF211, JK2, or JK36. After incubation for 20 min at 4 °C cells were washed and analyzed by flow cytometry. Dashed lines = unstained cells.