Pathogenicity of Campylobacter jejuni: Virulence associated factors and development of in vivo campylobacteriosis model.
AuthorBabakhani, Farah Kondori.
Committee ChairJoens, Lynn
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractCompetitive inhibition assays were performed to study the effect of various bacterial and host derived factors on the attachment and invasion of Campylobacter jejuni to HEp-2 cell lines. Campylobacter jejuni outer membrane or mammalian extracellular matrix components did not inhibit attachment of the bacteria to HEp-2 cells. Conversely, sodium chloride inhibited the attachment of C. jejuni to HEp-2 cells. This inhibition increased with higher salt concentrations, indicating that the attachment may have been mediated through charge interactions. Penetration of C. jejuni into the HEp-2 epithelial cells was significantly inhibited by 1B4 monoclonal antibody in competitive inhibition assays. Western blot analysis with 1B4 monoclonal antibody identified an epitope on antigens of 64-44 KDa in lysates prepared from invasive and non-invasive isolates and in antigens of 42-38 KDa in lysates prepared from only invasive C. jejuni strains. Proteinase K and sodium meta-periodate treatment of C. jejuni lysate changed the mobility of antigens recognized by 1B4 monoclonal antibody, suggesting that the antigens required for HEp-2 invasion may be glycoprotein in nature. Specific antisera, prepared in rabbits against the 1B4-affinity purified antigens, were able to block the invasion of C. jejuni into HEp-2 cells, demonstrating the specificity of 1B4 monoclonal antibody to the invasin antigen(s). Western blot analysis revealed that this specific antisera identified distinct antigens at 62, 47 and between 42-35 KDa in the lysates prepared from invasive strains. A primary intestinal cell line was developed using swine enterocytes to investigate and examine the validity of in vitro findings in relation to invasiveness of C. jejuni. One of the C. jejuni isolates (F1474) invaded swine enterocytes in significantly higher numbers. However, the invasive ability of C. jejuni T13192 increased dramatically during the third, fourth and fifth experimental trials. Recovered colonies from C. jejuni T13192 appeared highly mucoid and invaded tissue culture cells in higher numbers than the original isolate. The data not only support the previous in vitro findings regarding the invasiveness of C. jejuni, but also suggest that invasiveness of C. jejuni may be an inducible event. An in vivo model system was developed by inoculating colostrum deprived newborn piglets orally with an invasive strain of C. jejuni. Lesions similar to those in humans with campylobacteriosis were observed mainly in the large intestine. Damage to the epithelial cells and the presence of intracellular bacteria were the salient features of the lesion.
Degree ProgramMicrobiology and Immunology