Contact with cultured epithelial cells stimulates secretion of Salmonella typhimurium invasion protein InvJ

• Published in: Infection and Immunity Vol. 63; no. 10; pp. 4024 - 4028
• Main Authors: Zierler, M.K. (State University of New York, Stony Brook, NY.), Galan, J.E
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.10.1995
• Subjects: Antigens, Bacterial; BACTERIA; Bacterial Adhesion; Bacterial Proteins - secretion; Bacteriology; Biological and medical sciences; Cells, Cultured; CELLULE; CELULAS; CULTIVO DE CELULAS; CULTURE DE CELLULE; EPITELIO; EPITHELIUM; Epithelium - microbiology; ESTIMULO; Fundamental and applied biological sciences. Psychology; INFECCION; INFECTION; Intestines - microbiology; LOCI; LOCUS; Microbiology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Protein Biosynthesis; PROTEINAS; PROTEINE; SALMONELLA TYPHIMURIUM; Salmonella typhimurium - physiology; SECRECION; SECRETION; SERUM SANGUIN; STIMULUS; SUERO SANGUINEO; Proteins; Secretion; Interaction; Bacteria; Host agent relation; Epithelial cell; Salmonella typhimurium; Invasion; Enterobacteriaceae
• DOI: 10.1128/iai.63.10.4024-4028.1995
• ISSN: 0019-9567

Contact of Salmonella typhimurium with cultured epithelial cells results in the assembly of surface appendages termed invasomes which are presumably required for the internalization of these organisms into host cells. The assembly of these structures requires the function of a dedicated protein secretion system encoded in the inv locus. We show in this report that contact of wild-type S. typhimurium with cultured Henle-407 cells stimulated the secretion of InvJ, a recently identified target of the inv-encoded type III protein secretion system. Stimulation of InvJ secretion also occurred upon bacterial contact with bovine calf serum-coated culture dishes but did not occur upon S. typhimurium contact with glutaraldehyde-fixed Henle-407 cells. The stimulation of InvJ secretion did not require de novo protein synthesis. Invasion-defective invC and invG mutants of S. typhimurium failed to secrete InvJ upon contact with live Henle-407 cells. In contrast, contact-dependent secretion of InvJ in S. typhimurium invE mutants occurred at levels equivalent to those of the wild type. These results indicate that the presence of Henle-407 cells and/or serum is capable of activating the type III secretion system encoded in the inv locus, further supporting the notion that Salmonella entry into cultured cells is the result of a biochemical cross-talk between the bacteria and the host cells