Quantification of HtrA and LPS by dual labelled immunoflourescence during acute and heat shocked culture of C. trachomatis L2. The Figure shows the immunoflourescence on co-labelled slides of LPS (A, D) HtrA (B, E) and overlays (C, F) during acute at 23 h PI (A-C) and heat shocked for 3 h at 42°C at 20 h PI (23 h PI). Quantification of the HtrA immunoflourescence (as a ratio of LPS immunoflouresence) under each condition is indicated in the box below the Figure. #The quantification was conducted using the Leica software suite on individually selected inclusions with a minimum of 20 separate inclusions included in each analysis, *standard deviation is indicated in parantheses. The immunolabelling was conducted as per Methods, under identical laser conditions on the same day between the acute and heat shocked slides to allow quantification of fluorescence. Note: The argon laser to detect the emission of the FITC in (480–550 nm) collection region is at 100% laser power in these images due to the marked reduction in LPS present after heat shock, most other images presented in this paper with LPS-FITC labelling have been collected on 23% argon laser power. Scale bars (10 μM) are shown in the bottom right of each figure.