The mechanisms of cell-mediated resistance to listeriosis have been intensively studied but the roles of cellular c omponents in virulence are poorly understood. I am investigating the possible roles of 3 surface components in the virulence of Listeria. Descendants of these cells are responsible for the monocytosis characteristic of the infection and enter tissues a s macrophages. Using MPA and ISA and inbred strains of mice with known abnormalities in macrophage function we hope to understand the regulation of macrophage production and the effect of enhanced numbers of macrophages at key times during infection in normal and selectively compromised hosts. Motility may facilitate access to nutrients in the environment.
Listeria exhibits a peculiar tumbling motility.
We have demonstrated that motility is directional at 25o and 37o and have obtained nonmotile mutants using transposon mutagenesis. Using th ese mutants we will investigate the role of motility in virulence and the significance of motility in the economy of this versatile organism. Chemotaxis in Listeria monocytogenes. Galsworthy, S.B. and Fewster, D. 1988. Comparison of responsiveness to the monocytosis-producing activity of Listeria monocytogenes in mice genetically susceptible or resistant to listeriosis.