A single dose of irradiation reduces the number of chlamydial inclusions within host cells.

<p>(A) <i>C. trachomatis</i>-infected HeLa cells were either irradiated or not 40 hpi. Cultures were fixed 43 hpi and immunolabelled with anti-chlamydial LPS (green) and DAPI (blue). Frequency of inclusions per nucleus was calculated (mean ± SD; * p<0.001; n = 3; <i>t</i> test). (B) Infected HeLa cultures were collected and subjected to sub-passage titer analysis. Inclusion forming units (IFU) are shown as percent of control (mean ± SD; * p<0.0025; n = 3; <i>t</i> test). (C) Vero monolayers infected with <i>C. pecorum</i> were irradiated 40 hpi. Non-irradiated, <i>C. pecorum</i>-infected cells were used as controls. Cultures were incubated for 46 hours, fixed, and processed as in panel A (mean ± SD; * p<0.0025; n = 3; <i>t</i> test). (D) <i>C. pecorum</i>-infected Vero cells were separated from the supernatant, collected 43 hpi and subjected to sub-passage titer analysis. Monolayers were fixed 40 h post reinfection and immunolabelled as shown in panel A. Inclusion forming units are shown as percent of control (mean ± SD; * p<0.0001; n = 3; <i>t</i> test). Representative microscopic pictures at 1000× magnification are shown additionally in the panel. (E) The supernatant of the infected cells (panel D) was collected separately and subjected to sub-passage titer analysis. Inclusion forming units are represented as percent of control (mean ± SD; * p<0.01; n = 3; <i>t</i> test). Representative pictures are presented as well.