TY - JOUR

T1 - The fimbrial protein FlfA from Gallibacterium anatis is a virulence factor and vaccine candidate

AU - Bager, Ragnhild Jørgensen

AU - Nesta, Barbara

AU - Pors, Susanne Elisabeth

AU - Soriani, Marco

AU - Serino, Laura

AU - Boyce, John D.

AU - Adler, Ben

AU - Bojesen, Anders Miki

PY - 2013

Y1 - 2013

N2 - The Gram-negative bacterium Gallibacterium anatis is a major cause of salpingitis and peritonitis in egg-laying chickens, leading to decreased egg production worldwide. Widespread multidrug resistance largely prevents treatment of this organism using traditional antimicrobial agents, while antigenic diversity hampers disease prevention by classical vaccines. Thus, insight into its pathogenesis and knowledge about important virulence factors is urgently required. A key event during the colonization and invasion of mucosal surfaces is adherence, and recently, at least three F17-like fimbrial gene clusters were identified in the genomes of several G. anatis strains. The objective of this study was to characterize the putative F17-like fimbrial subunit protein FlfA from G. anatis 12656-12 and determine its importance for virulence. In vitro expression and surface exposure of FlfA was demonstrated by flow cytometry and immunofluorescence microscopy. The predicted function of FlfA as a fimbrial subunit protein was confirmed by immunogold electron microscopy. An flfA deletion mutant (ΔflfA) was generated in G. anatis 12656-12, and importantly, this mutant was significantly attenuated in the natural chicken host. Furthermore, protection against G. anatis 12656-12 could be induced by immunizing chickens with recombinant FlfA. Finally, in vitro expression of FlfA homologs was observed in a genetically diverse set of G. anatis strains, suggesting the potential of FlfA as a serotype-independent vaccine candidate This is the first study describing a fimbrial subunit protein of G. anatis with a clear potential as a vaccine antigen.

AB - The Gram-negative bacterium Gallibacterium anatis is a major cause of salpingitis and peritonitis in egg-laying chickens, leading to decreased egg production worldwide. Widespread multidrug resistance largely prevents treatment of this organism using traditional antimicrobial agents, while antigenic diversity hampers disease prevention by classical vaccines. Thus, insight into its pathogenesis and knowledge about important virulence factors is urgently required. A key event during the colonization and invasion of mucosal surfaces is adherence, and recently, at least three F17-like fimbrial gene clusters were identified in the genomes of several G. anatis strains. The objective of this study was to characterize the putative F17-like fimbrial subunit protein FlfA from G. anatis 12656-12 and determine its importance for virulence. In vitro expression and surface exposure of FlfA was demonstrated by flow cytometry and immunofluorescence microscopy. The predicted function of FlfA as a fimbrial subunit protein was confirmed by immunogold electron microscopy. An flfA deletion mutant (ΔflfA) was generated in G. anatis 12656-12, and importantly, this mutant was significantly attenuated in the natural chicken host. Furthermore, protection against G. anatis 12656-12 could be induced by immunizing chickens with recombinant FlfA. Finally, in vitro expression of FlfA homologs was observed in a genetically diverse set of G. anatis strains, suggesting the potential of FlfA as a serotype-independent vaccine candidate This is the first study describing a fimbrial subunit protein of G. anatis with a clear potential as a vaccine antigen.

KW - Amino Acid Sequence

KW - Animals

KW - Bacterial Proteins

KW - Bacterial Vaccines

KW - Chickens

KW - Cloning, Molecular

KW - Fimbriae, Bacterial

KW - Gene Deletion

KW - Gene Expression Regulation, Bacterial

KW - Molecular Sequence Data

KW - Pasteurellaceae

KW - Pasteurellaceae Infections

KW - Poultry Diseases

KW - Sequence Alignment

KW - Virulence Factors

U2 - 10.1128/IAI.00059-13

DO - 10.1128/IAI.00059-13

M3 - Journal article

C2 - 23509151

VL - 81

SP - 1964

EP - 1973

JO - Infection and Immunity

JF - Infection and Immunity

SN - 0019-9567

IS - 6

ER -