title: Yersinia pestis and host macrophages: immunodeficiency of mouse macrophages induced by YscW.
abstract: The virulence of the pathogenic Yersinia species depends on a plasmid-encoded type III secretion system (T3SS) that transfers six Yersinia outer protein (Yop) effector proteins into the cytoplasm of eukaryotic cells, leading to disruption of host defence mechanisms. It is shown in this study that Yersinia pestis YscW, a protein of the T3SS injectisome, contributes to the induction of a deficiency in phagocytosis in host macrophages and a reduction in their antigen-presenting capacity. A Y. pestis strain lacking yscW had no effect on uptake by host macrophages. In mice infected with wild-type Y. pestis, the yscW mutant or a complement strain, immunodeficiency was observed in host macrophages compared with those from uninfected mice. However, the phagocytosis and antigen presenting capacities of macrophages infected by yscW mutant strain both in vivo and in vitro were significantly higher than those by wild type strain. Consistent with this finding, when YscW was expressed in the RAW264.7 macrophage cell line, phagocytosis and antigen-presenting capacities were significantly lower than those of the control groups. These results indicate that Y. pestis YscW may directly induce immunodeficiency in murine macrophages by crippling their phagocytosis and antigen-presenting capacities. These data provide evidences to Y. pestis pathogenesis that some proteins in T3SS injectisome, such as YscW protein, might play independent roles in disrupting host defense apart from their known functions.
authors.affiliation: State Key laboratory of Pathogen and Biosecurity, National Center for Biomedical Analysis, Army Center for Microbial Detection and Research, Institute of Microbiology and Epidemiology, Beijing, China.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Bi
authors.forename: Zongmin
authors.initials: Z
authors.lastname: Du
authors.forename: Yanping
authors.initials: Y
authors.lastname: Han
authors.forename: Zhaobiao
authors.initials: Z
authors.lastname: Guo
authors.forename: Yafang
authors.initials: Y
authors.lastname: Tan
authors.forename: Ziwen
authors.initials: Z
authors.lastname: Zhu
authors.forename: Ruifu
authors.initials: R
authors.lastname: Yang
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D002645:Chickens; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D054884:Host-Pathogen Interactions / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D010587:Phagocytosis / Q000276:immunology*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000276:immunology; D015009:Yersinia Infections / Q000276:immunology* / Q000382:microbiology; D015010:Yersinia pestis / Q000235:genetics / Q000472:pathogenicity*
chemical_list: D001426:Bacterial Proteins; D014409:Tumor Necrosis Factor-alpha