title: The OmpA-like protein Loa22 is essential for leptospiral virulence.
abstract: Pathogenic mechanisms of Leptospira interrogans, the causal agent of leptospirosis, remain largely unknown. This is mainly due to the lack of tools for genetic manipulations of pathogenic species. In this study, we characterized a mutant obtained by insertion of the transposon Himar1 into a gene encoding a putative lipoprotein, Loa22, which has a predicted OmpA domain based on sequence identity. The resulting mutant did not express Loa22 and was attenuated in virulence in the guinea pig and hamster models of leptospirosis, whereas the genetically complemented strain was restored in Loa22 expression and virulence. Our results show that Loa22 was expressed during host infection and exposed on the cell surface. Loa22 is therefore necessary for virulence of L. interrogans in the animal model and represents, to our knowledge, the first genetically defined virulence factor in Leptospira species.
authors.affiliation: Unité de Biologie des Spirochètes, Institut Pasteur, Paris, France.
authors.forename: Paula
authors.initials: P
authors.lastname: Ristow
authors.forename: Pascale
authors.initials: P
authors.lastname: Bourhy
authors.forename: Flávia Weykamp
authors.initials: FW
authors.lastname: da Cruz McBride
authors.forename: Claudio Pereira
authors.initials: CP
authors.lastname: Figueira
authors.forename: Michel
authors.initials: M
authors.lastname: Huerre
authors.forename: Patrick
authors.initials: P
authors.lastname: Ave
authors.forename: Isabelle Saint
authors.initials: IS
authors.lastname: Girons
authors.forename: Albert I
authors.initials: AI
authors.lastname: Ko
authors.forename: Mathieu
authors.initials: M
authors.lastname: Picardeau
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000502:physiology*; D001483:Base Sequence; D006224:Cricetinae; D004251:DNA Transposable Elements; D004195:Disease Models, Animal; D006168:Guinea Pigs; D007668:Kidney / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D007921:Leptospira interrogans / Q000378:metabolism / Q000472:pathogenicity*; D007922:Leptospirosis / Q000382:microbiology*; D008099:Liver / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D008168:Lung / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D013154:Spleen / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D014774:Virulence
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004251:DNA Transposable Elements; C078167:OMPA outer membrane proteins