title: Protection of epithelial cells from Salmonella enterica serovar Enteritidis invasion by antibodies against the SPI-1 type III secretion system.
abstract: Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) is one of the major causes of bacterial food-borne illness in humans. During the course of infection, Salmonella Enteritidis uses 2 type III secretion systems (T3SS), one of which is encoded on Salmonella pathogenicity island 1 (SPI-1). SPI-1 plays a major role in the invasion process. In the present study, we evaluated the effect of sera against the SPI-1 T3SS components on invasion in vitro using polarized human intestinal epithelial cells (Caco-2). Antisera to SipD protected Caco-2 cells against entry of wild-type Salmonella Enteritidis. On the other hand, sera against InvG, PrgI, SipA, SipC, SopB, SopE, and SopE2 did not affect Salmonella Enteritidis entry. To illustrate the specificity of anti-SipD mediated inhibition, SipD-specific antibodies were depleted from the serum. Antiserum depleted of SipD-specific antibodies lost its capacity to inhibit Salmonella Enteritidis entry. Thus, we demonstrate for the first time that antibodies against the SPI-1 needle tip protein (SipD) inhibit Salmonella Enteritidis invasion and that the SipD protein may be an important target in blocking SPI-1 mediated virulence of Salmonella Enteritidis.
authors.affiliation: University of Saskatchewan, Saskatoon, Canada.
authors.forename: Taseen S
authors.initials: TS
authors.lastname: Desin
authors.forename: Claudia S
authors.initials: CS
authors.lastname: Mickael
authors.forename: Po-King S
authors.initials: PK
authors.lastname: Lam
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Potter
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Köster
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000276:immunology; D002460:Cell Line; D004847:Epithelial Cells / Q000382:microbiology*; D006801:Humans; D026901:Membrane Transport Proteins / Q000276:immunology*; D011817:Rabbits; D012480:Salmonella Infections / Q000517:prevention & control*; D012477:Salmonella enteritidis / Q000276:immunology*; D037521:Virulence Factors / Q000037:antagonists & inhibitors* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; C419942:Spi1 protein, Salmonella; D037521:Virulence Factors