Effect of 405 nm on CCL2 production in C. trachomatis -infected epithelial cells. (A) HeLa cells were infected with C. trachomatis serovar E at a MOI of 5 (CTE5). (B) Infected cells were then exposed to varying doses of 405 nm at a range of energy densities (5-20 J/cm2) either promptly after infection or 24 h post-infection (post-24 h). The effect of 405 nm on CCL2 was assessed during active (B) and persistent stages induced with penicillin (C). Supernatants were collected and measured for CCL2 production using an ELISA. Treatments are grouped based on post-hoc comparisons for convenience. Mean ± SEM are plotted for the two replicated experiments. Statistical differences were determined post-hoc using a Bonferonni adjustment comparing all groups to C. trachomatis infected cells (CTE); *, P < 0.001.