Figure 4.

Serum is required to reverse the 4-PI-induced C. trachomatis growth inhibition. HeLa cells were left untreated or pre-treated for 24 h with 1 mM 4-PI in serum-free or serum-containing complete medium. The cells were infected with C. trachomatis with an MOI of 1 and after 24 h p.i. cells either maintained in medium or the medium replaced. Cholesterol without or with different concentrations of FBS in the medium was added as supplement. Cells were harvested 48 h p.i. and fresh HeLa cells infected with dilutions of the harvested samples to titrate the C. trachomatis IFU. All titrations are the mean of three biologically independent replicate samples and error bars represent SD.