[WS4-2/ODP-010] Analysis of Legionella-containing vacuoles in Paramecium hosts
Legionella pneumophila is the causative agent of Legionnaires’ disease, which causes serious pneumonia in humans. We have studied the ecology of L. pneumophila in the environment using Paramecium as a protist host model. L. pneumophila is able to survive for a long period within the vacuoles by establishing symbiotic relationships with Paramecium. In this study, we focused on the maturation and constituent molecules of Legionella-containing vacuoles (LCVs) in Paramecium, and investigated in detail the mechanism by which Paramecium allows symbiosis of L. pneumophila. The antibody which recognizes vacuole membrane were obtained from National BioResource Project. After infection with L. pneumophila, the properties of LCVs in Paramecium were analyzed by immunostaining with the antibody. In addition, the antigen protein was detected by Western blotting. After taken up by Paramecium, L. pneumophila stayed in the vacuole, and the accumulation of molecule which was recognized by the antibody was observed in the membrane of LCVs. On the other hand, when a peculiar L. pneumophila strain that does not show the symbiotic relationships with Paramecium was taken in, the similar accumulation was inhibited. In Western blotting, the molecular weight of the antigen was estimated to be around 100 kDa. Currently, we are proceeding with the identification of the antigen by mass spectrometry.