Naslov
Maturation of Legionella pneumophila-containing phagosome into lysosome within IFN-gamma activated macrophages

Autori
Šantić, Marina ; Molmeret, Maelle ; Abu Kwaik, Yousef

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
11th Annual Midwest Microbial Pathogenesis Conference. Abstract book / Mulks, Martha ; Arvidson, Cindy - : ASM, 2004, 55-56

Skup
11th Annual Midwest Microbial Pathogenesis Conference

Mjesto i datum
Sjedinjene Američke Države, 01.10.2004. - 03.10.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Legionella; IFN-gamma; macrophages

Sažetak
Legionella pneumophila is an intracellular pathogen that modulates biogenesis of its phagosome to evade endocytic vesicle traffic, and this is mediated by the Dot/Icm type IV secretion system. In quiescent macrophages the Legionella-containing phagosome (LCP) does not acquire an endocytic marker and interacts with the endoplasmic reticulum (ER). Here we show that intracellular replication of L. pneumophila is inhibited in IFN-gamma activated mice macrophages and IFN-gamma activated human monocytes derived macrophages (hMDM) in a dose-dependent manner. We show that this inhibition of intracellular replication is associated with the maturation of LCP into phagolysosome. Within 1-2h of infection of IFN-gamma activated hMDMs, 90% of the LCPs co-localize with the late endosomal/lysosomal marker Lamp-2, and 80% of the LCP co-localize with the lysosomal marker Cathepsin D. In addition, IFN-gama activated hMDMs in which the lysosomes are loaded with the lysosomal tracer Texas-Red ovaalbumin (Trov), 70% of the LCPs co-localize with Trov. This phagolysosomal fusion is further confirmed by electron microscopy in which the lysosomes of IFN-gama activated hMDMs are pre-loaded with BSA-gold, and the BSA-gold particle are contained within the LCPs. While the LCPs within quiescent hMDMs show 95% colocalization with ER marker KDEL, the ER marker co-localize only with ~20% of the LCPs within IFN-gamma activated hMDMs. We conclude that IFN-gamma activated hMDMs, biogenesis of the LCPs is not modulated and they are trafficked into phagolysosomes for bacterial degradation.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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