Date of Award

Fall 1997

Project Type


Program or Major


Degree Name

Doctor of Philosophy

First Advisor

Thomas G Pistole


Salmonellosis continues to be a major infectious disease in both the United States and elsewhere. The outer membrane porin proteins (Omp) from Salmonella typhimurium play a key role in the initial adherence of this microorganism to murine macrophages and this mechanism is a critical event in the pathogenesis of infections. In this study macrophages were found to make contact with an OmpC-like protein of S. typhimurium and inhibition assays using the purified protein significantly reduced bacterial binding to macrophage. The ompC gene in a strain of S. typhimurium that is resistant to killing by macrophage was inactivated by transposon mutagenesis. Bacterial binding assays with these ompC-deficient bacteria and isogenic wild-type strains confirmed the role of the OmpC protein in mediating bacterial adherence to macrophages. The ompC gene of S. typhimurium was amplified using a polymerase chain reaction and the corresponding nucleotide sequence indicated that this gene was unique to our test strain. These results support the role of porin proteins as ligands in the initial adherence of this pathogen to host defense cells and may be helpful in developing strategies for disease prevention.