title: Intracellular spread of Shigella flexneri associated with the kcpA locus and a 140-kilodalton protein.
abstract: Escherichia coli K-12 hybrids carrying both the 220-kilobase plasmid and the purE-linked kcpA locus from Shigella flexneri expressed a 140-kilodalton (kDa) protein which was recognized by convalescent sera from monkeys infected with S. flexneri. These hybrids were tested for the ability to produce plaques in HeLa cell monolayers. Hybrid strains which carried both the 220-kilobase plasmid and the kcpA locus had a plaque-forming efficiency of at least 10(-4) PFU/CFU, whereas the plaque-forming efficiency of hybrids that carried only the shigella invasion plasmid ranged from undetectable to 10(-6). Variants were purified from the rare plaques formed by E. coli hybrids that carried only the shigella invasion plasmid. These plaque-purified strains also expressed the 140-kDa protein, and they had a plaque-forming efficiency of at least 10(-4). Transduction of the purE locus from a plaque-purified hybrid into a non-plaque-forming E. coli K-12 strain did not alter the phenotype of the recipient, but conjugation of the shigella invasion plasmid into this transductant reconstituted both expression of the 140-kDa protein and the plaque-forming phenotype. Invasive E. coli K-12 hybrids carrying only the shigella invasion plasmid remained localized within discrete areas of the HeLa cell cytoplasm, whereas hybrids that also carried the S. flexneri kcpA locus grew in a dispersed pattern throughout the host cell cytoplasm. The dispersal of these organisms was inhibited by cytochalasin D, which suggested that host cell microfilaments may play a role in the intracellular spread of enteroinvasive pathogens.
authors.affiliation: Department of Enteric Infections, Walter Reed Army Institute of Research, Washington, D.C. 20307.
authors.forename: T
authors.initials: T
authors.lastname: Pál
authors.forename: J W
authors.initials: JW
authors.lastname: Newland
authors.forename: B D
authors.initials: BD
authors.lastname: Tall
authors.forename: S B
authors.initials: SB
authors.lastname: Formal
authors.forename: T L
authors.initials: TL
authors.lastname: Hale
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D001426:Bacterial Proteins / Q000235:genetics*; D001562:Benzimidazoles / Q000494:pharmacology; D001826:Body Fluids / Q000382:microbiology*; D015169:Colony Count, Microbial; D003593:Cytoplasm / Q000187:drug effects / Q000382:microbiology / Q000648:ultrastructure; D004405:Dysentery, Bacillary / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000648:ultrastructure; D005798:Genes, Bacterial; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D007424:Intracellular Fluid / Q000382:microbiology*; D008870:Microtubules / Q000187:drug effects; D008970:Molecular Weight; D015739:Nocodazole; D012763:Shigella flexneri / Q000254:growth & development / Q000472:pathogenicity* / Q000648:ultrastructure; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D001562:Benzimidazoles; D015739:Nocodazole