Brucella invasion of human intestinal epithelial cells elicits a weak proinflammatory response but a significant CCL20 secretion

FERRERO MC; FOSSATI CA; RUMBO M; BALDI PC

FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Hoboken, NJ; Año: 2012 vol. 66 p. 45 - 57

0928-8244

In spite of the frequent acquisition of Brucella infection by the oral route inhumans, the interaction of the bacterium with cells of the intestinal mucosahas been poorly studied. Here, we show that different Brucella species caninvade human colonic epithelial cell lines (Caco-2 and HT-29), in which onlysmooth species can replicate efficiently. Infection with smooth strains did notproduce a significant cytotoxicity, while the rough strain RB51 was more cytotoxic.Infection of Caco-2 cells or HT-29 cells with either smooth or roughstrains of Brucella did not result in an increased secretion of TNF-a, IL-1b,MCP-1, IL-10 or TGF-b as compared with uninfected controls, whereas all theinfections induced the secretion of IL-8 and CCL20 by both cell types. TheMCP-1 response to flagellin from Salmonella typhimurium was similar inBrucella-infected or uninfected cells, ruling out a bacterial inhibitory mechanismas a reason for the weak proinflammatory response. Infection did notmodify ICAM-1 expression levels in Caco-2 cells, but increased them in HT-29cells. These results suggest that Brucella induces only a weak proinflammatoryresponse in gut epithelial cells, but produces a significant CCL20 secretion. Thelatter may be important for bacterial dissemination given the known ability ofBrucella to survive in dendritic cells.