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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have reported that some strains of Pseudomonas aeruginosa can enter corneal epithelial cells during experimental murine eye infection and when the cells are cultured in vitro. Following invasion, both the host cell and the intracellular bacteria can remain viable for up to 24 h. Others have reported that toxin-mediated damage of epithelial cells contributes to the pathogenesis of P. aeruginosa keratitis. To clarify the relationship between cell invasion and cytotoxicity, fourteen P. aeruginosa isolates were compared for their capacity to enter epithelial cells and for their ability to induce cytotoxicity. Bacterial invasion was quantified by gentamicin survival assays both in vivo and in vitro. Cytotoxicity was examined qualitatively by trypan blue exclusion assays and quantitatively by chromium release assays in vitro. A significant inverse correlation was found between the ability to induce cytotoxicity and epithelial cell invasion as measured by gentamicin survival assays. Both cytotoxic and noncytotoxic strains were identified among corneal and noncorneal isolates; all isolates that were not cytotoxic were capable of epithelial cell invasion. Efficient host cell invasion could not be demonstrated for cytotoxic strains; however, the gentamicin survival assay relies upon host cells retaining viability in order to yield useful results, and this may limit the effectiveness of this assay for testing epithelial cell invasion by cytotoxic strains. Since all of the corneal isolates that were tested were virulent in vivo, the results show that there are at least two different types of P. aeruginosa-induced disease, one caused by strains that are cytotoxic and the other involving bacteria that can enter epithelial cells and survive intracellularly without killing the host cell.
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PMID:Relationship between cytotoxicity and corneal epithelial cell invasion by clinical isolates of Pseudomonas aeruginosa. 867 39

Acanthamoeba spp. are free-living amebae associated with amebic keratitis and chronic granulomatous amebic encephalitis. The present studies were undertaken to compare the pathogenicity of three species of Acanthamoeba in B6C3F1 mice after intranasal challenge with Acanthamoeba-induced cytopathogenicity for different macrophage populations. The ability of murine macrophage cell lines and activated murine peritoneal macrophages to lyse Acanthamoeba has been assessed by coincubating macrophages with 3H-uridine labeled amebae. Conversely, destruction of macrophages by Acanthamoeba was determined by measuring the release of chromium-51 from radiolabeled macrophages. Acanthamoeba culbertsoni, which is highly pathogenic for mice, destroys macrophage cultures in vitro. Activated primary peritoneal macrophages were more resistant to Acanthamoeba-mediated destruction than macrophage cell lines activated in vitro. Activated macrophages were capable of limited destruction of Acanthamoeba polyphaga and Acanthamoeba castellanii. Acanthamoeba-specific antibodies increased the amebicidal activity of activated macrophages. Macrophage-mediated destruction was by contact-dependent cytolysis and by ingestion of amebae. Conditioned medium obtained from macrophage cultures after treatment with lipopolysaccharide and interferon gamma was neither cytolytic nor cytostatic for Acanthamoeba spp. Purified recombinant cytokines including tumor necrosis factor alpha, interleukin 1 alpha, and interleukin 1 beta, alone or in combination, were not cytolytic for Acanthamoeba trophozoites.
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PMID:The interaction of Acanthamoeba spp. with activated macrophages and with macrophage cell lines. 970 82