The passenger domain of PmpD is secreted outside <i>Chlamydia</i> and accumulated in the inclusion lumen during the life cycle of <i>C. trachomatis.</i>

<p>McCoy cells were infected with <i>C. trachomatis</i> serovar L2 and fixed with methanol at 16 (A and E), 24 (B and F), 36 (C and G), and 48 (D and H) h p.i. and reacted with mAb against chlamydial MOMP (green) in combination with pAb against fragment 2 of PmpD (red) (A–D) or pAb against chlamydial HSP60 protein (red) (E–H) (internal control). Arrow indicates localization of PmpD during the chlamydial life cycle on the surface of <i>Chlamydia</i> (A) or in the inclusion lumen outside <i>Chlamydia</i> (red spots) (B–D). When reacted with anti-HSP60 pAb, no material was visible outside <i>Chlamydia</i>. The photographs were made using a Leica SL confocal microscope.