
Extrusions are phagocytosed and promote Chlamydia survival within macrophages
Author(s) -
Zuck Meghan,
Ellis Tisha,
Venida Anthony,
Hybiske Kevin
Publication year - 2017
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/cmi.12683
Subject(s) - biology , chlamydia trachomatis , intracellular parasite , chlamydia , macrophage , immune system , intracellular , microbiology and biotechnology , extracellular , phagocytosis , immunology , genetics , in vitro
The precise strategies that intracellular pathogens use to exit host cells have a direct impact on their ability to disseminate within a host, transmit to new hosts, and engage or avoid immune responses. The obligate intracellular bacterium Chlamydia trachomatis exits the host cell by two distinct exit strategies, lysis and extrusion. The defining characteristics of extrusions, and advantages gained by Chlamydia within this unique double‐membrane structure, are not well understood. Here, we define extrusions as being largely devoid of host organelles, comprised mostly of Chlamydia elementary bodies, and containing phosphatidylserine on the outer surface of the extrusion membrane. Extrusions also served as transient, intracellular‐like niches for enhanced Chlamydia survival outside the host cell. In addition to enhanced extracellular survival, we report the key discovery that chlamydial extrusions are phagocytosed by primary bone marrow‐derived macrophages, after which they provide a protective microenvironment for Chlamydia . Extrusion‐derived Chlamydia staved off macrophage‐based killing and culminated in the release of infectious elementary bodies from the macrophage. Based on these findings, we propose a model in which C. trachomatis extrusions serve as “trojan horses” for bacteria, by exploiting macrophages as vehicles for dissemination, immune evasion, and potentially transmission.