Figure 4.

Internalization of fluorescein isothiocyanate (FITC)-chitooligosaccharide hexamer (COS6) by macrophages with or without blocking mannose receptor (MR) CTLD4-8. Anti-MR CTLD4-8 (4 μg/ml) and D-mannose (2 mg/ml) blockade of the cells for 2 h, and the macrophages were incubated with FITC-COS in a six-well plate at 28°C for 30 min. (A) The internalization rate of FITC-COS6 by flow cytometry. The mean fluorescence intensity (MFI) of internalization in macrophages was recorded. (B) Inhibitors of MR binding and function block the association of COS with primary macrophage. Cells were preincubated with 2 mg/ml D-mannose, mannose receptor C-type lectin-like domain 4-8 of Megalobrama amblycephala (MaMR-CTLD4-8) specific antibody, negative IgG, or medium alone. Then, 0.05 mM FITC-COS6 was added, and cells were incubated, washed, lysed, and mixed uniformly. Fluorescence intensity was measured. Data were shown as means ± SD and collected from three independent experiments, with (*) p < 0.05 and (**) p < 0.01 vs. the COS6 group (set as 100).