Fetal liver-derived macrophages from wild type and Cx43−/− mice can phagocytose zymosan, and are capable of phagosome acidification. (A) Wild type (black line) and Cx43−/− (gray line) macrophages were incubated with zymosan particles labeled with pHrodo for 60 min at 4°C (left panel), or at 37°C (right panel), (shaded black peak represents macrophages not treated with zymosan). (B) Percentage of cells positive for labeled zymosan after incubation at 4°C (left panel), or at 37°C (right panel). (C) Mean fluorescence intensity (MFI) of pHrodo signal in macrophages incubated at 4°C (left panel), or at 37°C (right panel), (averages from 3 experiments, error bars depict S.E.M.).