In another line of research, we have shown that fibrinogen can act as a bridging molecule in the adherence of S. aureus to catheters and cultured endothelial cells. We are in the process of generating polyclonal and monoclonal antibodies to characterize the biological significance of this protein. In our third investigative program, we are interested in phase switching of the agr phenotype in S. aureus. The agr locus is a global regulator involved in the control of extracellular and cell wall proteins. Given that some of these proteins regulated by agr are potential virulence determinants, it is conceivable that this phase switching may be an important event in controlling the expression of these proteins in S. aureus infections.
Studies are under way to characterize the genes involved in phase switching.
Cheung, A. L., M. Krishnan, E. A. Jaffe, and V. A. Fischetti. Fibrinogen acts as a bridging molecule in the adherence of Staphylococcus aureus to cultured human endothelial cells. Journal of Clinical Investigation. Cheung, A. L., and S. J. Projan. Journal of Bacteriology.