Figure 1. Mouse CD16 blocks MDALDL binding to macrophages.

A, CD16 inhibits J774 adhesion. MDALDL-coated ELISA plates were treated with indicated reagents (at 2 μg/ml) or buffer for 30 min. Calein-labeled J774 cells were added to the plates and incubated at 4°C for 30 min. After removing non-adherent cells by inverting the plates in PBS for 5 min, cell adhesion (%) was calculated by dividing fluorescence before and after washing the plate to remove non-adherent cells. B, Dose dependent MDALDL binding to RAW264 cells. RAW264 cells were incubated with MDALDL^biotin at indicated concentration for 1 h at 4°C and binding followed by streptavidin-PE. Cells incubated without MDALDL^biotin was used as a negative control. MDALDL binding was determined by FACS analysis. C, CD16 inhibits MDALDL binding to RAW264 macrophages. MDALDL^biotin (10 μg/ml) was preincubated without (buffer) or with sCD16 (5 μg/ml) for 2 h followed by its binding to RAW264 cells. D–G, Recombinant sCD16 blocks MDALDL binding to CD16. sCD16 or indicated soluble scavenger receptors were coated onto ELISA white plate. MDALDL^biotin was preincubated with 2.5 μg/ml sCD16 or buffer for 2 h and added to sCD16- (D) or sCD36 (E), sLOX-1 (F) or sSR-A- (G) coated plates. Binding was detected using streptavidin-alkaline phosphatase and Lumiphos 530 luminescence substrate as described in methods. In all these experiments values are means ± SD triplicate wells. Shown is a representative of three independent experiments. P, <0.01** or <0.001*** compared to buffer treated wells (no competitor).