a, b Murine CD18, CD11a, CD11b and CD47 were immunoprecipitated from non-stimulated WT and Cd47−/− BMN lysates and immunoblotted for CD47 as detailed in the methods. a Representative western blot confirming the expression of CD47 in total lysates from WT but CD47 loss in Cd47−/− BMN. b CD47 was co-immunoprecipitated with CD11b and CD18, and, to a lesser extent, with CD11a on WT BMN. Cd47−/− BMN were used as negative control. c The association between CD47 and CD11b on unstimulated, non-permeabilized BMN was confirmed by in situ proximal ligation assay (PLA) using a combination of CD47 and CD11b Abs as detailed in the methods. The positive fluorescent staining (white dots) indicates close proximity (<40 nm) between CD47 and CD11b targets. Positive controls include use of CD11b-CD18 Abs as a known heterodimeric interaction. Furthermore, as a negative control, CD47-CD11b interaction was probed on BMN from Cd47−/− mice and no signal was detected. Nuclei were counter-stained with Hoechst 33342. 100x objective. Scale bars: 50 μm.