Galectin-5 modulates exosome uptake by macrophages. PKH67-labeled exosomes (60 μg protein/mL) were incubated with macrophages for 3 hours at 37°C. After washing, cell fluorescence intensity was measured by flow cytometry. Tinted patterns always indicate cell autofluorescence. Data obtained after incubation of PKH67-labeled exosomes alone with macrophages are represented by a solid black line. PKH67-labeled exosomes were incubated with peritoneal (A) or J774 (B) macrophages in the presence of purified Gal-5 (50μM; dashed line), unlabeled exosomes (300 μg protein/mL; dotted line), or BSA (50μM; dashed line). (C) PKH67-labeled exosomes were incubated with peritoneal macrophages in the presence of GST–Gal-5 (50μM; dashed line) or GST (50μM; dotted line). (D) PKH67-labeled exosomes and GST–Gal-5 (50μM) were incubated with peritoneal macrophages after preincubation (1 hour, RT) of GST–Gal-5 in 150 mM lactose (dotted line) or glucose (gray solid line) or medium alone (dashed line).