title: Role of a new intimin/invasin-like protein in Yersinia pestis virulence.
abstract: A comprehensive TnphoA mutant library was constructed in Yersinia pestis KIM6 to identify surface proteins involved in Y. pestis host cell invasion and bacterial virulence. Insertion site analysis of the library repeatedly identified a 9,042-bp chromosomal gene (YPO3944), intimin/invasin-like protein (Ilp), similar to the Gram-negative intimin/invasin family of surface proteins. Deletion mutants of ilp were generated in Y. pestis strains KIM5(pCD1(+)) Pgm(-) (pigmentation negative)/, KIM6(pCD1(-)) Pgm(+), and CO92. Comparative analyses were done with the deletions and the parental wild type for bacterial adhesion to and internalization by HEp-2 cells in vitro, infectivity and maintenance in the flea vector, and lethality in murine models of systemic and pneumonic plague. Deletion of ilp had no effect on bacterial blockage of flea blood feeding or colonization. The Y. pestis KIM5 Δilp strain had reduced adhesion to and internalization by HEp-2 cells compared to the parental wild-type strain (P < 0.05). Following intravenous challenge with Y. pestis KIM5 Δilp, mice had a delayed time to death and reduced dissemination to the lungs, livers, and kidneys as monitored by in vivo imaging using a lux reporter system (in vivo imaging system [IVIS]) and bacterial counts. Intranasal challenge in mice with Y. pestis CO92 Δilp had a 55-fold increase in the 50% lethal dose ([LD(50)] 1.64 × 10(4) CFU) compared to the parental wild-type strain LD(50) (2.98 × 10(2) CFU). These findings identified Ilp as a novel virulence factor of Y. pestis.
authors.affiliation: Departments of Basic Sciences, Mississippi State University, Mississippi State, Mississippi, USA.
authors.forename: Keun Seok
authors.initials: KS
authors.lastname: Seo
authors.forename: Jong Wan
authors.initials: JW
authors.lastname: Kim
authors.forename: Joo Youn
authors.initials: JY
authors.lastname: Park
authors.forename: Austin K
authors.initials: AK
authors.lastname: Viall
authors.forename: Scott S
authors.initials: SS
authors.lastname: Minnich
authors.forename: Harold N
authors.initials: HN
authors.lastname: Rohde
authors.forename: Darren R
authors.initials: DR
authors.lastname: Schnider
authors.forename: Seung Yong
authors.initials: SY
authors.lastname: Lim
authors.forename: Joon Bae
authors.initials: JB
authors.lastname: Hong
authors.forename: B Joseph
authors.initials: BJ
authors.lastname: Hinnebusch
authors.forename: Jason L
authors.initials: JL
authors.lastname: O'Loughlin
authors.forename: Claudia F
authors.initials: CF
authors.lastname: Deobald
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Bohach
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Hovde
authors.forename: Scott A
authors.initials: SA
authors.lastname: Minnich
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D017930:Genes, Reporter; D056945:Hep G2 Cells; D006801:Humans; D008164:Luminescent Proteins; D051379:Mice; D009154:Mutation; D010930:Plague / Q000382:microbiology* / Q000635:transmission; D060888:Real-Time Polymerase Chain Reaction; D005423:Siphonaptera / Q000382:microbiology; D014774:Virulence; D015010:Yersinia pestis / Q000378:metabolism* / Q000472:pathogenicity*
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008164:Luminescent Proteins; C053476:invasin, Yersinia