Active migration into the subcellular space precedes Campylobacter jejuni invasion of epithelial cells.
The bacterial pathogen Campylobacter jejuni invades mucosal cells via largely undefined and rather inefficient (0.01-2 bacteria per cell) mechanisms. Here we report a novel, highly efficient C. jejuni infection pathway resulting in 10-15 intracellular bacteria per cell within 3 h of infection. Electron microscopy, pulse-chase infection assays and time-lapse multiphoton laser confocal microscopy demonstrated that the mechanism involved active and rapid migration of the pathogen into the subcellular space (termed 'subvasion'), followed by bacterial entry ('invasion') at the cell basis. Efficient subvasion was maximal after repeated rounds of selection for the subvasive phenotype. Targeted mutagenesis indicated that the CadF, JlpA or PEB1 adhesins were not required. Dissection of the selected and parental phenotypes by SDS-PAGE yielded comparable capsule polysaccharide and lipooligosaccharide profiles. Proteomics revealed reduced amounts of the chemotaxis protein CheW for the subvasive phenotype. Swarming assays confirmed that the selected phenotype exhibited altered migration behaviour. Introduction of a plasmid carrying chemotaxis genes into the subvasive strain yielded wild-type subvasion levels and migration behaviour. These results indicate that alterations in the bacterial migration machinery enable C. jejuni to actively penetrate the subcellular space and gain access to the cell interior with unprecedented efficiency.
Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands.
Lieke B
LB
van Alphen
Nancy M C
NM
Bleumink-Pluym
Klazina D
KD
Rochat
Bas W M
BW
van Balkom
Marc M S M
MM
Wösten
Jos P M
JP
van Putten
D018829:Adhesins, Bacterial / Q000235:genetics / Q000502:physiology; D000942:Antigens, Bacterial / Q000235:genetics / Q000502:physiology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics; D016123:Campylobacter jejuni / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004847:Epithelial Cells / Q000382:microbiology* / Q000648:ultrastructure; D005816:Genetic Complementation Test; D006801:Humans; D042541:Intracellular Space / Q000382:microbiology* / Q000648:ultrastructure; D008070:Lipopolysaccharides / Q000032:analysis; D008124:Locomotion / Q000502:physiology; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D018715:Microscopy, Video; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D011135:Polysaccharides, Bacterial / Q000032:analysis; D020543:Proteome / Q000032:analysis; D017422:Sequence Analysis, DNA
D018829:Adhesins, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C107872:CadF protein, Campylobacter jejuni; D002352:Carrier Proteins; D004269:DNA, Bacterial; D008070:Lipopolysaccharides; C489977:PEB1 protein, Campylobacter; D011135:Polysaccharides, Bacterial; D020543:Proteome; C023023:lipid-linked oligosaccharides; C051236:CheW protein, Bacteria