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Title: Infection of cell cultures with Campylobacter derived from the porcine proliferative enteropathies
Author: Okereke, Rowland Eugene
ISNI:       0000 0001 3455 9054
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1985
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This Btudy utilised cell cultures in an attempt to elucidate the aetiological cause of the bacterial associated porcine proliferative enteropathies. Initial work evaluated the attachment of one possible agent Campylobacter sputorum subspecies mucosalis (CSM) to cells, CSM did not adhere to PK15 cells during the first 8 hours of cellular development whereas, after 20-24 hours of growth, the majority of cells in the monolayer showed maximum bacterial attachment. Adhesion was influenced by the number of viable organisms in the inoculum, by the degree of cell to cell contact in the monolayer and by the stage of development of the cells when exposed to infection, but, in all instances, a small number of cells were refractory to bacterial attachment. Adhesion to PK15 cells was completely inhibited by rabbit anti-CSM serum, partially inhibited by wheat germ agglutinin (WGA) and soya bean agglutinin (SBA) but was not affected by any of the metallic salts tested. Attachment of CSM to in vitro preparations of pig intestinal brush borders was scanty compared with that obtained with PK15 cells and did not vary between cells from different pig genotypes. Following attachment to PK15 cell surfaces, the bacteria were engulfed and later appeared within phagosomes or lying freely in the cytoplasm. Cytopathic effects were induced by CSM infecting doses of at least 81og^Q organisms per ml but not by 51og1Q organisms per ml. Bacterial counts of supernatant fluids and lysed cells from infected PK15 cultures, supported by immunoflourescence staining, indicated cell-associated growth of CSM but limited survival in the extracellular fluids. Infection of tissue culture cells by CSM grown in cell-free culture (CSM-C) was compared with that of bacteria derived directly from the tissues of the proliferative enteropathies. Three types of bacteria were isolated from filtered homogenised PIA tissues. A purified inoculum of the filtrate prepared by dilution and further filtration contained organisms that stained as the intracellular organisms, grew in cell-free culture and were identified as CSM (CSM-T). Such CSM-T derived by filtration produced cytopathic changes in PK15 cells similar to those obtained with cultured CSM (CSM-C). Progressive infection of cell cultures was initiated with only 3»481og1_ per ml of CSM-T, but not with 5»26log..Q per ml of CSM-C. Irrespective of source, whether from lesions, tissue culture or cell-free cultures, it was not possible to passage CSM organisms serially in PK15 cells. Campylobacter-like forms in filtrates of PHE tissues did not multiply in PK15 cells nor produce cytopathic changes. In contrast, Campylobacters and other bacteria isolated from PIA or PHE by filters of larger pore diameter multiplied in the extracellular fluids and caused rapid destruction of PK15 cells. The novel intracellular, campylobacter-like antigen (CJ) of proliferative porcine enteropathies and hamster ileitis, which differs from the surface antigen of known Campylobacters, was also detected in PK15 cells following infection with CSM-C or CSM-T organisms. A line of PK15 cells, once-infected with CSM and subsequently self-cured, was developed but the cells showed only minor differences in characteristics from those of the parent line. The significance and future applications of the findings of this present investigation in relation to the pathogenesis of porcine proliferative enteropathies, the diseases associated with intracellular Campylobacters are discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Veterinary sciences & veterinary medicine