title: Biosafety level 2 model of pneumonic plague and protection studies with F1 and Psa.
abstract: Attenuated Yersinia pestis pgm strains, such as KIM5, lack the siderophore yersiniabactin. Strain KIM5 does not induce significant pneumonia when delivered intranasally. In this study, mice were found to develop pneumonia after intranasal challenge with strain KIM5 when they were injected intraperitoneally with iron dextran, though not with iron sulfate. KIM5-infected mice treated daily with 4 mg iron dextran died in 3 days with severe pneumonia. Pneumonia was less severe if 4 mg iron dextran was administered only once before infection. The best-studied experimental vaccine against plague currently consists of the Yersinia pestis capsular antigen F1 and the type 3 secreted protein LcrV. The F1 antigen was shown to be protective against KIM5 infections in mice administered iron dextran doses leading to light or severe pneumonia, supporting the use of an iron dextran-treated model of pneumonic plague. Since F1 has been reported to be incompletely protective in some primates, and bacterial isolates lacking F1 are still virulent, there has been considerable interest in identifying additional protective subunit immunogens. Here we showed that the highly conserved Psa fimbriae of Y. pestis (also called pH 6 antigen) are expressed in murine organs after infection through the respiratory tract. Studies with iron dextran-treated mice showed that vaccination with the Psa fimbrial protein together with an adjuvant afforded incomplete but significant protection in the mouse model described. Therefore, further investigations to fully characterize the protective properties of the Psa fimbriae are warranted.
authors.affiliation: Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Estela M
authors.initials: EM
authors.lastname: Galván
authors.forename: Manoj Kumar Mohan
authors.initials: MK
authors.lastname: Nair
authors.forename: Huaiqing
authors.initials: H
authors.lastname: Chen
authors.forename: Fabio
authors.initials: F
authors.lastname: Del Piero
authors.forename: Dieter M
authors.initials: DM
authors.lastname: Schifferli
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology* / Q000502:physiology; D001426:Bacterial Proteins / Q000276:immunology* / Q000502:physiology; D003264:Containment of Biohazards; D004195:Disease Models, Animal; D005260:Female; D007155:Immunologic Factors / Q000008:administration & dosage*; D007505:Iron-Dextran Complex / Q000008:administration & dosage*; D051379:Mice; D008810:Mice, Inbred C57BL; D010930:Plague / Q000382:microbiology* / Q000473:pathology; D037521:Virulence Factors / Q000276:immunology / Q000502:physiology; D015010:Yersinia pestis / Q000276:immunology / Q000472:pathogenicity*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007155:Immunologic Factors; D037521:Virulence Factors; C086725:caf1 protein, Yersinia pestis; C081814:pH 6 antigen, Yersinia; D007505:Iron-Dextran Complex