Absence of cytokine response to bacterial challenge in human tubuloepithelial cells

In acute bacterial renal infections, which are most frequently caused by Es cherichia coli, tubuloepithelial cells are involved with respect to bacteri al adherence, invasion and cytotoxicity. In addition, cytokines expressed b y tubuloepithelial cells may be relevant for the recruitment of inflammator y cells and tissue damage in bacterial interstitial nephritis. We asked whi ch inflammatory cytokines are produced by primary human tubuloepithelial ce lls following in vitro exposure to E, coli and found no release of IL-6, IL -8 and TNF-alpha by tubular cells challenged by bacteria. Purified virulenc e factors (fimbriae, lipopolysaccharide) from E. coli were also without eff ects on cytokine release by tubular cells. Since lymphocytic infiltration i s a characteristic feature in the chronic form of interstitial nephritis, M HC class II expression by tubular cells in response to bacterial coincubati on was analyzed. Exposure to both IFN-gamma and E. coli enhanced MHC class II expression on tubuloepithelial cells. In conclusion, tubuloepithelial ce lls may play an active role in the local defense against bacteria, e.g, by expressing MHC class II molecules. However, in vitro inflammatory cytokines are not induced by E, coli in this cell population. Copyright (C) 2001 S. Karger AG. Basel.