FIGURE 3.
Non-opsonized LDL and acLDL binding to CHO cells was investigated by flow cytometry. CHO and CHO-CR1 bound LDL (10 μg/ml) in a similar proportion, but binding of acLDL (10 μg/ml) was less clear (A). Binding of labeled LDL was reduced when CHO were pre-incubated with increasing concentrations of anti-human LDL receptor antibodies (B). Comparable reductions in LDL binding to CHO were observed when labeled (fluorescent) LDL (10 μg/ml) was combined with increasing concentrations of native (non-labeled) LDL (C) or normal human serum (NHS) (D) due to competitive binding between labeled and non-labeled LDL. The dotted horizontal lines represent the autofluorescent background signal.