FIG. 4.

Host sphingomyelin uptake in C. pneumoniae-infected cells. HeLa cells and monocyte-derived macrophages were simultaneously infected with C. pneumoniae at an MOI of 20. The infected cells were labeled with C₆-NBD-ceramide and subjected to 4 h of back-exchange. (A to E) Uptake of fluorescent sphingomyelin by C. pneumoniae at 5 h (A) and 48 h (B) postinfection in HeLa cells and at 5 h (C), 48 h (D), and 72 h (E) postinfection in macrophages. (F) C₆-NBD-ceramide labeling of C. pneumoniae-infected HeLa cells after 48 h in the presence of 50 μg/ml ampicillin, as previously described (50). The arrows indicate C. pneumoniae inclusions. Scale bar = 10 μm.