FIG. 3.

Cytadherence is important for C. pneumoniae infection-induced cytokine gene expression. A549 cells were either left untreated (Con), infected with C. pneumoniae (C.p.), or incubated with 100 U of heparin (Hep)/ml. For heparin treatment of C. pneumoniae, the bacterium was incubated with heparin (Hep+C.p.) at concentrations of 10, 50, and 100 U/ml for 1 h; the mixtures were then used to infect A549 cells. Ten hours later, the total RNA was extracted and cellular levels of IL-8 and TNF-α were measured by RT-PCR. β-Actin was used as an internal control. Densitometric quantification of the electrophoretograms for IL-8 and TNF-α RT-PCR products are shown below the gel pictures and normalized to β-actin. The densitometric values of Hep+C.p. were compared to those of C.p. and analyzed by Student's t test. **, P < 0.01.