Figure 4

Comparison of specific surface binding and HRP uptake in RBMM and 43^MRcells. (A) Cells (5 x 10⁵) were incubated on ice for 60 minutes with approximately 0.4 μg of ¹²⁵I-Man-BSA in 100 μl of binding buffer in the presence or absence of mannan (1 mg/ml). Cells with bound ligand were separated from the unbound ligand by centrifugation thorough oil. Cell-associated radioactivity was quantified by gamma counting. Results are representative of three independent experiments. (B) RBMM, U937 43neg and 43^MR cells were incubated with 8 μg of HRP in 400 μl of Hanks’ balanced salt solution (HBSS) containing 1% BSA in the presence or absence of mannan (1 mg/ml). Cells were incubated at 37°C for 60 minutes, then washed twice in HBSS and solubilized in 0.1% Triton X-100. Cell associated HRP activity was determined by quantitation of phenol red oxidation in the presence of hydrogen peroxide at 610 nm.