Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Veterinary Microbiology and Preventive Medicine


An immunogenic lipopolysaccharide (LPS)-protein complex isolated from Pasteurella multocida (strain P-2383; capsular type A and somatic type 3) was characterized. To determine the presence of LPS in the complex, chemical composition of LPS of P. multocida was first characterized in comparison with LPS of several Gram-negative bacterial pathogens by gas chromatography (GC) on a capillary column. The GC analysis indicated that the chemical composition of P. multocida LPS was influenced by the extraction methods. When LPS from several Gram-negative bacteria was examined, heterogeneity in the chemical composition of LPS of different origin was found not only in the O-specific polysaccharide but also in the core polysaccharide. The LPS of closely related bacteria shared more fatty acid constituents with each other than with unrelated bacteria. The GC analysis demonstrated the presence of LPS in the LPS-protein complex. However, there apparently was more carbohydrate than fatty acid in the complex in contrast to LPS extracted from whole bacteria in which fatty acid seemed to be in excess. The toxicity of the complex as well as its LPS moiety in chicken embryos was less than that for the purified LPS. The complex was determined to contain at least 32 protein and polysaccharide components by SDS-PAGE analysis; at least 18 components reacted with an antiserum against the complex as determined by Western immunoblot assay. There was no significant compositional variation between the complexes from different strains of the same serotype. The complex provided substantial cross-protection in mice against different strains of the serotype. However, fractions of the complex prepared by phenol-water treatment lacked immunogenicity. The protein fraction was extremely blastogenic for mouse B cells while the original complex had limited activity. Although hyperimmune serum against the complex protected mice against challenge thereby indicating a role for humoral immunity, the complex was also found to induce cell-mediated immunity including a blastogenic response of T cells to the complex, delayed-type hypersensitivity reaction in the hind footpad and suppressive effect on growth of Salmonella enteritidis in the immune mice.



Digital Repository @ Iowa State University,

Copyright Owner

Hyoik Ryu



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File Format


File Size

153 pages

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Microbiology Commons